The Indian Contract Act, 1872
7. Acceptance must be absolute
In order to convert a proposal into a promise the acceptance must –
(1) be absolute and unqualified.
(2) be expressed in some usual and reasonable manner, unless the proposal prescribes the manner in which it is to be accepted. If the proposal prescribes a manner in which it is to be accepted; and the acceptance is not made in such manner, the proposer may, within a reasonable time after the acceptance is communicated to him, insist that his proposal shall be accepted in the prescribed manner, and not otherwise; but; if he fails to do so, he accepts the acceptance.
Acceptance must be unqualified and without condition
The cardinal principle in the light of section 7 of the Act is that the offer and acceptance of an offer must be absolute without giving any room of doubt. It is well settled that the offer and acceptance must be based or founded on three components—Certainty, commitment and communication. If any one of three components is lacking either in the offer or in the acceptance there cannot be a valid contract; Kilburn Engineering Ltd. v. Oil and Natural Gas Corporation Ltd., AIR 2000 Bom 405.
When the acceptor puts in a new condition while accepting, the contract already signed by the proposer is not complete until the proposer accepted the condition; Haridwar Singh v. Begum Sumbrui, AIR 1972 SC 1942.
An acceptance with a variation is no acceptance; it is simply a counter proposal which must be accepted by the original promisor before a contract is made; Haji Mohd. Haji Jiva v. E. Spinner, (1900) 24 Bom 510.
No second acceptance
The rule of law is that a mere offer to sell property, which can be withdrawn at any time, and which is made dependant on the acceptance of the person to whom it is made, is a mere nudum pactum. The person to whom, the offer has been made, cannot, by acceptance make a binding contract after he knows that the person who has made the offer has sold the property to someone else; Dickinson v. Dodds, 1876 Ch. D. 463.