Free consent is not present when there is a bilateral mistake of fact at the time a contract is executed. The Contract Act of 1872 considers bilateral mistakes and lack of free consent under different clauses. If there is a bilateral mistake about an essential matter of fact, section 20 states the contract is void. However, if the mistake is minor and does not affect the essence of the contract, it may be voidable. For a contract to be enforceable, free consent is required, and if consent is not free due to a bilateral mistake, the nature of the mistake determines whether the contract is void or voidable.