In every contract of sale, there are certain expressed and implied conditions and warranties. The term implied conditions means conditions which can be inferred from or guessed from the context of the contract.
1) Conditions as to Title
In the case of sale, seller has a right to sell the goods. The buyer can assume that the seller has a right to sell the goods.
Eg. 'R' purchased a motorcar from 'D' and used it for 4 months. Later after six months, true owner came and proved that he is a true owner.
In this case, 'R' has to return the car to the true owner and claim the full price paid by him from 'D'.
2) Conditions as to Description
In a contract of sale by description, there is an implied condition that goods supplied should agree with the descriptions made by the seller.
Eg. 'A' has bought a machinery from 'B' who described it to be just one year old. After buying the machinery and using it for a month, 'A' came to know that it is very old machinery.
In this case, 'A' can return the machinery to 'B' on the ground that machinery is not as per the description i.e. not recent one.
3) Conditions as to Merchantability
If goods are bought by description and the seller is a dealer in goods of that description, the implied condition is that goods must be of merchantable quality.
It only means that the goods must be saleable in the market under that denomination.
"A watch that will not keep time, a pen that will not write and tobacco which will not smoke, cannot be regarded as merchantable under such names."

(i) Appropriation is a process by which the goods to be delivered under the contract of sale are identified and isolated with the consent of the seller as well as the buyer.
(ii) It is a bilateral act of the seller and the buyer to identify and isolate the goods.
(iii) In other words, where the goods identified and isolated are put into boxes or any container with the consent of the buyer, it is called appropriation.
Eg. 'A' agrees to sell 'B' the oil to be produced by him. The oil was filled by 'A' into the bottles supplied by 'B'. It is an effective appropriation and the ownership of oil goods passes to the buyer when the oil is filled into the bottles.
In this case, the buyer gave his consent to the appropriation by supplying the bottles.

Right of an Unpaid Seller against the Buyer Personally
(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 Damage 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 the contract till the date of payment of purchase price.

Rights of an Unpaid Seller against the Goods
(1) Right of Lien: 
An unpaid seller has a right to retain the goods till he receives the price. But to exercise this lien
(i) He must be in possession of goods
(ii) The goods must have been sold without any stipulation as to credit or where goods have been sold on credit, the terms of credit must have expired.
(iii) It must be remembered that the right of lien depends on actual possession of goods
Where the Property in the Goods has Passed to the Buyer.
(2) Right of Stoppage in Transit: 
Where the seller has delivered the goods to a carrier or other bailee for the purpose of transmission to the buyer, but the buyer has not acquired them, then the seller can stop the goods and regain the possession. 
(3) Right of Resale:
The unpaid seller can resell the goods
(i) Where they are of a perishable nature or
(ii) After exercising his right of lien or stoppage in transit, even though he has given intimation to the buyer of his intention to resell, buyer has not tendered the price within a reasonable time.
(iii) Where the seller has expressly reserved the right of resale in the contract itself.