- Official section
- National V.B: Contract Types
- Broker weight
- Part of 19% of the national portion
- Expected scored items
- The current PSI broker outline assigns about 19 of 100 scored national items to Contracts
Contracts exam concept
Bilateral vs. unilateral contracts
Do not count the people. Ask what the offeror asked the other person to do. If the offer requests a return promise, the exchange is bilateral. If it requests completion of an act, the exchange is unilateral. That acceptance test is more reliable than trying to memorize which real estate document belongs in which box.
Last updated: August 1, 2026
What is the difference at a glance?
Short answer: A bilateral contract exchanges promise for promise, so both parties are bound when valid acceptance occurs. A unilateral contract exchanges the offeror's promise for the offeree's requested performance, so acceptance occurs through performance. A purchase agreement is normally bilateral, a reward is the classic unilateral offer, and an option combines a contract to keep an offer open with an underlying offer the optionee may choose to exercise. Identify the offer, requested acceptance, consideration, acceptance event, and remaining duties.
Real agreements can combine promises, conditions, and performance, and courts interpret the actual language and conduct rather than an exam label. Modern brokerage agreements often impose mutual obligations even though older study examples describe some open listings as unilateral. Illinois's current written-agreement rules also require specific brokerage content and conduct. This guide uses the national exam distinction and primary sources reviewed through August 1, 2026.
What changes from one term to the next?
- Terms
- Bilateral vs. unilateral
- Difference
- Bilateral exchanges a promise for a promise. Unilateral exchanges a promise for requested performance.
- Question cue
- What did the offer request as acceptance?
- Terms
- Two parties vs. two promises
- Difference
- Both contract types involve at least two sides. Bilateral classification comes from exchanged promises, not merely the number of participants.
- Question cue
- Count the promised commitments, not the names.
- Terms
- Return promise vs. preparation
- Difference
- A requested return promise can accept a bilateral offer. Preparation to perform a unilateral offer is not automatically the requested completed act.
- Question cue
- Commitment communicated versus getting ready.
- Terms
- Performance vs. promise to perform
- Difference
- Performance supplies the requested result. A promise to perform is a present commitment to supply that result later.
- Question cue
- Act completed versus duty undertaken.
- Terms
- Bilateral vs. executory
- Difference
- Bilateral describes formation through promises. Executory describes unfinished performance. A purchase agreement is commonly both.
- Question cue
- Formation structure versus performance stage.
- Terms
- Unilateral vs. one-sided unfairness
- Difference
- Unilateral is a formation structure, not a finding that terms are unfair, unconscionable, or imposed by one party.
- Question cue
- Requested acceptance versus quality of bargain.
- Terms
- Option contract vs. purchase contract
- Difference
- The option binds the optionor to keep an offer available. Proper exercise can create the purchase contract on the stated terms.
- Question cue
- Right to choose versus mutual sale duties.
- Terms
- Reward offer vs. gift promise
- Difference
- A reward seeks a specified act in exchange for payment. A gift promise does not seek bargained performance as its price.
- Question cue
- Requested exchange versus generosity alone.
- Terms
- Open listing vs. exclusive listing
- Difference
- An open listing can emphasize payment for a completed result. An exclusive listing commonly includes mutual duties, but the actual writing controls.
- Question cue
- Result-based offer versus continuing service promises.
- Terms
- Express vs. bilateral
- Difference
- Express describes how terms are communicated in words. Bilateral describes the promise-for-promise exchange. A contract can be both.
- Question cue
- Mode of expression versus acceptance structure.
How does the distinction change the answer?
Accepted residential purchase agreement
Scenario: A buyer promises to pay $340,000 on the stated terms, and the seller promises to convey the identified home at closing.
- The seller's promise induces the buyer's promise and vice versa.
- Both sides become obligated at formation, subject to contingencies and other terms.
- Future closing performance makes it executory, a separate classification.
Answer: This is a bilateral contract formed by an exchange of promises.
Reward for returning a lost abstract
Scenario: An owner publicly promises $500 to the person who finds and returns a lost original abstract of title. A person who knows of the offer returns it as requested.
- The owner requested the completed return, not a promise to search.
- The person supplied the precise requested act with knowledge of the offer.
- The performance supplies consideration for the reward promise.
Answer: This is the classic unilateral-contract pattern.
Promise to search is not the reward performance
Scenario: After seeing the reward, a neighbor tells the owner, I promise to look tomorrow, but never finds or returns the abstract.
- The offer requested return of the item.
- The neighbor supplied only a promise to try.
- That promise is not the acceptance event the unilateral offer specified.
Answer: No reward contract formed from the promise alone.
Modern exclusive listing with mutual duties
Scenario: A written exclusive listing requires the sponsoring broker to market, present offers, and provide minimum services, while the seller promises cooperation and the stated compensation when earned.
- The broker undertakes present service obligations.
- The seller undertakes connected contractual promises.
- The classification comes from those mutual promises, not the word listing.
Answer: The agreement is bilateral on these terms.
Paid option to purchase
Scenario: An owner accepts consideration and promises to keep a $420,000 sale offer open for 30 days. The option holder may buy but has no duty to do so.
- The owner is bound to hold the offer open during the option period.
- The holder purchased a choice rather than promising to buy.
- A timely valid exercise can create the purchase obligations described in the option.
Answer: This is an option contract supporting a unilateral offer, followed by a bilateral purchase contract if properly exercised.
Open compensation offer tied to a result
Scenario: An owner signs a nonexclusive agreement promising compensation to the first authorized broker who produces the stated ready, willing, and able buyer, and the writing imposes no continuing marketing promise on a broker.
- The owner seeks a completed result rather than a return promise from one exclusive broker.
- No broker is obligated merely to try under the stated facts.
- The exact written trigger and lawful compensation rules still control entitlement.
Answer: The result-based offer has a unilateral structure on these limited facts.
The O-F-F-E-R exchange test
- Offeror: identify who made the proposal and who received it.
- Form requested: find whether acceptance requires a promise, completed act, tender, notice, or specified combination.
- For exchange: identify the bargained consideration given for the offeror's promise.
- Event of acceptance: locate the communicated return promise or completed requested performance.
- Revocation and timing: test option protection, beginning performance, reliance, deadline, lapse, and notice.
- Result: classify bilateral or unilateral, then add separate labels for validity, writing, and performance status.
- Structure
- Bilateral
- Offer requests
- Return promise
- Acceptance event
- Promise communicated as required
- Typical example
- Accepted purchase agreement
- Structure
- Unilateral
- Offer requests
- Specified performance
- Acceptance event
- Requested act completed
- Typical example
- Reward for returning lost item
- Structure
- Option
- Offer requests
- Consideration for time to choose
- Acceptance event
- Option formed, then exercise governed separately
- Typical example
- Paid right to buy by a deadline
- Structure
- No bargain
- Offer requests
- No requested exchange
- Acceptance event
- No contractual acceptance
- Typical example
- Unsupported gift promise
Where do similar terms create traps?
- Trap
- Unilateral means one person
- Correction
- The term describes promise-for-performance acceptance, not the number of parties.
- Trap
- Bilateral means two signatures
- Correction
- Signatures can prove assent, but exchanged promises create the bilateral structure.
- Trap
- Every written contract is bilateral
- Correction
- Writing concerns form. A written reward or result-based offer can still request acceptance by performance.
- Trap
- Every oral contract is unilateral
- Correction
- Spoken parties can exchange promises and create a bilateral contract, subject to any writing requirement.
- Trap
- A purchase agreement is unilateral until closing
- Correction
- A normal accepted purchase agreement exchanges binding promises at formation and remains executory until performance.
- Trap
- A unilateral contract is unfair or voidable
- Correction
- Unilateral does not describe fairness, capacity, fraud, or avoidance rights.
- Trap
- Promising to perform accepts every unilateral offer
- Correction
- Acceptance requires the act the offer requested, unless the offer reasonably permits a promise instead.
- Trap
- Mere preparation always blocks revocation
- Correction
- Distinguish preparation from beginning the invited performance and apply the offer terms and governing law.
- Trap
- Every listing agreement is unilateral
- Correction
- Current agreements often contain mutual service and client promises. Read the writing.
- Trap
- The optionee promised to buy
- Correction
- An option ordinarily buys the right to choose. The optionee has no purchase duty before valid exercise.
- Trap
- A gift promise becomes unilateral when the recipient acts
- Correction
- The act must be bargained for as the requested price of the promise, not merely occur after a gratuitous statement.
- Trap
- Bilateral and executory are competing answers
- Correction
- A contract can be bilateral by formation and executory by performance status at the same time.
Can you separate the terms in a new fact pattern?
These questions are original study items aligned to the published outline. They are not copied, recalled, or predicted PSI questions.
1. A seller promises to convey a home, and the buyer promises to pay the stated price. What type of exchange is this?
- Bilateral contract
- Unilateral contract
- Void contract
- Executed contract
Show answer and explanation
Answer: Bilateral contract
The purchase agreement exchanges the seller's promise for the buyer's return promise.
2. An owner promises $300 to anyone who returns a lost survey. How is the offer accepted?
- By returning the survey as requested
- By privately intending to search
- By asking whether the reward is negotiable
- By promising to look next month
Show answer and explanation
Answer: By returning the survey as requested
The offer requests performance, making return of the survey the acceptance event.
3. Which statement about a unilateral contract is correct?
- It still involves an offeror and an offeree
- It has only one legal party
- It never requires consideration
- It is automatically unenforceable
Show answer and explanation
Answer: It still involves an offeror and an offeree
Unilateral describes the requested promise-for-performance exchange, not a one-person transaction.
4. A buyer pays consideration for the right, but not the duty, to purchase by September 1. Which concept is primary?
- Option contract
- Completed sale
- Bilateral purchase promise by the buyer
- Tenancy in common
Show answer and explanation
Answer: Option contract
The buyer purchased a choice while the owner promised to keep the underlying offer available for the stated period.
5. Which question best distinguishes bilateral from unilateral formation?
- Did the offer request a return promise or completed performance?
- How many pages were signed?
- Was the property residential?
- Did the deed record?
Show answer and explanation
Answer: Did the offer request a return promise or completed performance?
The requested mode of acceptance controls the basic classification.
Where do these ideas appear on the outline?
- Topic
- Bilateral contract
- What to know
- Promise for promise, mutual promises, offer, return promise, acceptance, immediate obligations, promisor, promisee, consideration, purchase agreement, lease, brokerage agreement, loan agreement, and executory performance
- Best exam move
- Choose bilateral when the requested acceptance is a commitment to perform, not the completed act itself.
- Topic
- Unilateral contract
- What to know
- Promise for performance, requested act, completion, reward, offeror, offeree, no return promise required, acceptance by conduct, knowledge of offer, consideration, revocation, beginning performance, and completion
- Best exam move
- Choose unilateral when the offer says, in substance, perform this act and I will pay or perform as promised.
- Topic
- Requested mode of acceptance
- What to know
- Offer language, promise, act, shipment, delivery, production of buyer, payment, notice, exercise, deadline, method, completion, reasonable interpretation, ambiguity, and surrounding circumstances
- Best exam move
- Read the acceptance instruction before classifying the contract.
- Topic
- Promise for promise
- What to know
- Seller promises conveyance, buyer promises payment, landlord promises possession, tenant promises rent, broker promises services, client promises compensation, lender promises funds, borrower promises repayment, mutuality, and future performance
- Best exam move
- The promises can bind now even though the parties will perform later.
- Topic
- Promise for performance
- What to know
- Reward, specified result, completed service, returned property, located owner, introduced buyer, delivered document, closed transaction, finished repair, accepted goods, no substitute promise, and exact condition
- Best exam move
- Confirm the offeree supplied the performance the offer actually requested.
- Topic
- Purchase agreement
- What to know
- Buyer promise, seller promise, price, conveyance, closing, earnest money, financing contingency, inspection contingency, title, deed, possession, default, remedy, and bilateral executory contract
- Best exam move
- Classify a normal accepted purchase agreement as bilateral and executory before closing.
- Topic
- Lease
- What to know
- Landlord promise, possession, quiet enjoyment, tenant promise, rent, maintenance, term, renewal, security deposit, mutual covenants, signing, future duties, bilateral, and executory
- Best exam move
- A conventional lease commonly contains enforceable promises on both sides.
- Topic
- Brokerage agreement
- What to know
- Sponsoring broker, client, written agreement, designated agent, marketing, showing, search, negotiation, minimum services, cooperation, compensation, term, termination, protection period, and mutual duties
- Best exam move
- Read the current agreement's promised services and client duties rather than assuming every listing is unilateral.
- Topic
- Open listing and compensation offer
- What to know
- Nonexclusive listing, owner, multiple brokers, procuring cause, ready willing and able buyer, completed result, offer of compensation, no exclusive promise, revocation, notice, and exact agreement terms
- Best exam move
- A result-based offer can be unilateral, but the written agreement may add bilateral obligations that change the classification.
- Topic
- Option contract
- What to know
- Optionor, optionee, consideration, specified time, irrevocable offer, no duty to buy, exercise, notice, method, expiration, purchase terms, underlying offer, and later bilateral sale contract
- Best exam move
- Separate the paid promise to keep the offer open from the purchase contract created by valid exercise.
- Topic
- Right of first refusal
- What to know
- Owner, holder, future decision to sell, third-party offer, triggering event, notice, match, election, deadline, no present purchase duty, promise, condition, and later transaction
- Best exam move
- Do not call every one-sided opportunity an option; classify the triggering promise and any later acceptance separately.
- Topic
- Acceptance by performance
- What to know
- Knowledge of offer, intent, exact requested act, substantial completion, full completion, tender, notification, silence, preparation, beginning performance, reasonable time, deadline, and proof
- Best exam move
- Performance must correspond to the offer; preparation or a different act does not automatically accept it.
- Topic
- Beginning performance
- What to know
- Start invited act, tender, substantial step, mere preparation, reliance, temporary irrevocability, reasonable opportunity, completion, offer terms, notice, state law, and exam simplification
- Best exam move
- Use completion as the basic acceptance rule, but recognize that beginning invited performance can limit revocation under applicable law.
- Topic
- Revocation
- What to know
- Offer withdrawn, communication, direct notice, reliable indirect notice, before acceptance, option, firm commitment, beginning performance, reliance, deadline, lapse, death, incapacity, and illegality
- Best exam move
- Ask whether the offer remained revocable and whether acceptance or protected performance had already occurred.
- Topic
- Consideration
- What to know
- Bargained exchange, return promise, requested act, forbearance, benefit, detriment, adequacy, nominal option consideration, past act, gift, illusory promise, preexisting duty, and earnest money
- Best exam move
- Find what the offeror sought and what the offeree gave in exchange.
- Topic
- Contract classifications can overlap
- What to know
- Bilateral, unilateral, valid, voidable, unenforceable, express, implied, executed, executory, written, oral, assignable, contingent, and independent labels
- Best exam move
- Use one label for formation structure and another for validity, form, or performance status.
- Topic
- Writing and electronic form
- What to know
- Statute of Frauds, land interest, signed memorandum, party to be charged, electronic record, electronic signature, agreement to transact electronically, attribution, retention, and no classification change
- Best exam move
- Written or electronic form does not decide whether the exchange is promise for promise or promise for performance.
- Topic
- Broker practice boundaries
- What to know
- Explain general structure, use approved form, no legal drafting, no unilateral alteration, written consent, deliver true copy within 24 hours, track acceptance, document performance, compensation terms, and attorney referral
- Best exam move
- Do not change the requested acceptance or compensation trigger through an informal promise outside the authorized written agreement.
How do you make the distinction stick?
- Session
- Session 1
- Focus
- Identify the requested acceptance
- Proof you are ready
- Underline the requested promise or performance in 25 offers before naming the contract type.
- Session
- Session 2
- Focus
- Map common real estate agreements
- Proof you are ready
- Classify purchase agreements, leases, listings, options, rights of first refusal, rewards, and compensation offers from their actual terms.
- Session
- Session 3
- Focus
- Test consideration
- Proof you are ready
- For 20 exchanges, identify the bargained return promise, performance, forbearance, or missing consideration.
- Session
- Session 4
- Focus
- Build acceptance timelines
- Proof you are ready
- Resolve offer, preparation, beginning performance, completion, notice, revocation, lapse, and option-protection events in order.
- Session
- Session 5
- Focus
- Separate overlapping labels
- Proof you are ready
- Describe 20 contracts using one formation label and separate validity, form, and performance labels.
- Session
- Session 6
- Focus
- Run the O-F-F-E-R test
- Proof you are ready
- Score at least 90% and state offeror, requested form, exchange, acceptance event, timing, and result for every miss.
Do not count recognition as mastery. Close the notes and explain the rule, apply it to a new fact pattern, and identify why each distractor fails.
Turn the comparison into a test-day decision
From concept to decision
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Questions students ask about Bilateral vs. Unilateral Contracts
What is a bilateral contract?
A bilateral contract is formed through an exchange of promises. Each party becomes a promisor and a promisee when the promises are accepted. A typical purchase agreement is bilateral: the seller promises to convey the property, and the buyer promises to pay the agreed price subject to the contract's terms.
What is a unilateral contract?
A unilateral contract is formed when an offer requests acceptance by completing a specified performance rather than by making a return promise. A classic example is a reward offer that promises payment to the person who performs the stated act. Until acceptance by performance, only the offeror has made the requested promise.
What is the easiest way to distinguish bilateral from unilateral?
Ask what the offer requests as acceptance. If it asks the offeree to promise, the resulting contract is bilateral. If it asks the offeree to perform the specified act, it is unilateral. Count the form of exchange, not the number of people, signatures, pages, payments, or future duties.
Is a real estate purchase agreement bilateral?
Usually yes. Once accepted, the buyer promises to purchase and pay while the seller promises to sell and convey. Contingencies can condition those duties, and the contract may remain executory until closing, but those facts do not change the basic promise-for-promise structure.
Does a unilateral contract have only one party?
No. A unilateral contract still involves an offeror and an offeree. Unilateral describes how acceptance and consideration are structured: one party promises something in exchange for the other party's requested performance. It does not mean a person makes a binding contract alone.
Is an option contract unilateral?
An option contains two connected pieces. The optionor is bound to keep an offer open for the option period in exchange for consideration, while the optionee is not obligated to buy. Illinois cases describe the option as a contract to leave a unilateral offer open. If the optionee exercises properly, the exercise can create the underlying bilateral purchase contract.
Is every listing agreement unilateral?
No. Classification depends on the actual promises. A modern written listing agreement can impose duties on the sponsoring broker and the client, making it bilateral. A true offer of compensation that requests only the completed production of a stated result can have unilateral features. Do not classify a document from its title alone.
How is a unilateral offer accepted?
It is accepted by the performance requested in the offer. Beginning performance can create legal protections against revocation under applicable law, but the exam's basic rule is that the requested result must be completed unless the offer states otherwise. Mere preparation is not automatically acceptance.
Do bilateral and unilateral contracts both require consideration?
Yes. In a bilateral contract, each return promise can supply consideration for the other. In a unilateral contract, the requested performance supplies consideration for the offeror's promise. A gratuitous promise with no bargained exchange is not made enforceable merely by calling it unilateral.
Are these official PSI exam questions?
No. They are original questions aligned to the national Contracts outline effective June 24, 2026. The current PSI bulletin, Illinois contract instructions, statutes, administrative rules, and official Illinois opinions were reviewed through August 1, 2026.
Primary sources
- PSI Illinois Candidate Information Booklet dated June 24, 2026
- Illinois Pattern Civil Jury Instructions 700.00, current contract formation and consideration principles
- In re Estate of Ness, 2013 IL App (2d) 121177-U, Illinois option structure
- Ross v. May Co., Illinois Appellate Court, bargained exchange of promise or performance
- 68 Illinois Administrative Code 1450.775, current written-agreement rules
- 68 Illinois Administrative Code 1450.770, current Illinois brokerage-agreement requirements
- 740 ILCS 80/2, current Illinois writing rule for interests in land
- 815 ILCS 333, current Illinois Uniform Electronic Transactions Act
The current official outline controls the tested scope. Statutes, regulations, and official agency materials control when a general study rule and a jurisdiction-specific rule differ.
Editorial status
Checked against primary sources
The Pass Illinois editorial team last checked this guide on August 1, 2026. Every practice question is an original study item, and the source links above let you verify the rules that support the lesson.