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?

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.

Asked by Aarti Batta | 11th Dec, 2014, 10:29: PM

Expert Answer:

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.

Answered by Prachi Sawant | 12th Dec, 2014, 05:36: PM