Question

Which of the following equations illustrates the law of conservation of matter?

Answer 1

Answer: The correct answer is option (B).

Explanation:

Law of conservation of mass: 'In a chemical reaction, mass neither be created nor be destroyed'

In the balance chemical equation,total mass of the reactants is equal to the total mass of the products.

A. $2Na+Cl_2\rightarrow NaCl$

$[2\times (23 g/mol)+(35.5 g/mol)\times 2]=[23 g/mol+35.5 g/mol]$

117 g/mol  ≠ 58.5 g/mol

Law of Conservation of Mass not followed.

B.$2Na+Cl_2\rightarrow 2NaCl$

$[2\times (23 g/mol)+(35.5 g/mol)\times 2]=2\times [23 g/mol+35.5 g/mol]$

117 g/mol  =  117 g/mol

Law of Conservation of Mass is followed.

C.$2Na+2Cl_2\rightarrow 2NaCl$

$[2\times (23 g/mol)+(35.5 g/mol)\times 2]=2\times [23 g/mol+35.5 g/mol]$

188 g/mol  ≠ 117 g/mol

Law of Conservation of Mass not followed.

D.$Na+Cl_2\rightarrow 2NaCl$

$[(23 g/mol)+(35.5 g/mol)\times 2]=2\times [23 g/mol+35.5 g/mol]$

94 g/mol  ≠ 117 g/mol

Law of Conservation of Mass not followed.

Hence, the correct answer is option (B).