An agreement is valid only if it is the result of the “free consent” of all the parties to it. Section 13 of the Contract Act defines the meaning of the term ‘consent’ and Section 14 specifies under what circumstances make that consent ‘free’.
Section 13: Two or more person are said to consent when they agree upon the same thing in the same sense.
It is essential to the creation of a contract that both parties agree to the same thing in the same sense, in which case they are said to be AD IDEM. So, if the parties are not “ad idem” on the subject matter about which they are negotiating, there will not be any real agreement between them. But only consent is not enough. There must be free consent.
Section 14: Consent is said to be free when it is not caused by –
(1) coercion, as defined in section 15, or
(2) undue influence, as defined in section 16, or
(3) fraud, as defined in section 17, or
(4) misrepresentation, as defined in section 18, or
(5) mistake, subject to the provisions of section 20,21, and 22.
Consent is said to be so caused when it would not have been given but for the existence of such coercion, undue influence, fraud, misrepresentation, or mistake.
So, we can say that free consent is the consent which is given in absence of Coercion, undue influence, Fraud, Misrepresentation or Mistake.