(i) A seller is deemed to be an unpaid seller (a) when the whole of the price has not been paid or (b) a bill of exchange or other negotiable instrument given to him has been dishonoured.
(ii) Thus it would be obvious that a seller who has received only a part of the price is also an unpaid seller.
(iii) Seller includes not only the actual seller but also an agent of a seller or a consignee.

(i) There is an implied warranty that the buyer shall have and enjoy quiet possession of the goods.
(ii) If the buyer's possession is disturbed by a person having a superior right to that of the seller, the buyer is entitled to claim the damages.

(i) A condition is a stipulation which is essential to the main purpose of the contract. It is core to the contract.
(ii) The non-fulfillment of the condition cancels the very contract.
(iii) E.g. 'A' intends to buy a motorbike from 'B. 'A' insists that the bike should give him a mileage of 50 km per litter.
(iv) He prefers to have a red color bike. 'B' a mechanic gets a bike which gives him 55 kms per litter.
(v) But the color is green. In this case, 'A' cannot cancel the contract.
(vi) Since 'A'. is very particular about the mileage, it is a condition to the contract.
(vii) That part of the contract is fulfilled by 'B'. However, 'A' can ask the mechanic 'B' to bear the cost of repainting it with red color.

(i) Transfer of property (ownership) in goods from the seller to the buyer is the main object of a contract of sale.
(ii) The term property in goods must be distinguished from possession of goods.
(iii) Property in goods means the ownership of goods while possession of goods refers to the custody of goods or control over the goods.
(iv) For eg. 'A'  may possess a watch. Just because 'A' possesses the watch, he cannot be owner. He might have borrowed the watch from his friend or stolen the watch from somebody or found it on the highways. In this case, he cannot be called owner.

(i) Specific Goods: 
Specific goods denote goods identified and agreed upon at the time of contract of sale. For eg, if a buyer selects a particular variety of saree after examining several other sarees, the selected one denotes specific goods.
(ii) Ascertained Goods:
The term ascertained goods is also used as similar in meaning to specific goods. But this term may even refer to goods which become ascertained subsequent to the formation of the contract.
(iii) Unascertained or Generic Goods:
These are goods which are not identified and agreed upon at the time of contract of sale. For eg, A wants to buy a car from a showroom where different models at different prices have been displayed. All these displayed models represent unascertained goods.

(i) Suit for price: 
Where the ownership in the goods has passed to the buyer and the buyer refuses to pay for the goods, the seller can file a case against the buyer for the price.
(ii) Suit for Damages for Non-acceptance: 
Where the buyer wrongfully refuses to accept the goods, the seller can sue him for damages for non-acceptance of the goods.
(iii) Suit for Cancellation of the Contract before the Due Date: 
Where the buyer cancels the contract before the date of delivery, the seller may either treat the contract as continuing or wait till the due date or he can file a case against buyer immediately.
(iv) Suit for Interest: 
Where there is a specific agreement between buyer and seller regarding charging interest on the price, the seller can recover interest from the buyer from the due date of contract till the date of payment of purchase price.