plz explain this answer

A student heats 25g of reactant 'A' with 50g of reactant 'B'. He obtains 25g of product 'C' and recovers 25 g of unreacted 'A'. Which of the following law is confirmed in the following reaction?

 Law of multiple proportion

 Law of constant proportion

 Law of conservation of mass and Law of constant proportion

 Law of conservation of mass

Solution

Correct Option:  Law of conservation of mass

Explanation:

 

 Law of conservation of mass is confirmed from the reaction since mass of reactants is equal to mass of products.

Dear sharnamaarti@gmail.com

Thanks for asking us a question in Ask the Expert section of TopperLearning.com.

There are two mistakes in the above question. The question should go as given below:

A student heats 25g of reactant 'A' with 50g of reactant 'B'. He obtains 50g of product 'C' and recovers 25 g of unreacted 'B'. Which of the following law is confirmed in the following reaction?

 

Solution: Two laws are followed in this question.

First law is Law of definite proportion as follows:

Here 25 g of reactant A reacts with 50 g of reactant B to produce 50 g of product C. That means 25 g of A consumes only 25 g of B. The ratio is 1:1. Even if there would have been say 75 g B is present, still only 25 g of B will react with 25 g of A. Or if 10 g of B is present then only 10 g of A will react and remaining 15 g of A will remain unreacted.

Second law of is Law of conservation of mass as follows:

There is 25 g of A and 50 g of B. That means total 75 g of reactant is present. On product side 50 g of C and 25 g of unreacted B is present. That means total 75 g of produt is present.

Hence, the correct option will be "Law of conservation of mass and Law of constant proportion".

 

 

Regards

Topperlearning Team.