Question

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

A. 2Na + Cl2 NaCl
B. 2Na + Cl2 2NaCl
C. 2Na + 2Cl2 2NaCl
D. Na + Cl2 2NaCl

Answer 1

Answer: The correct answer is option (B).

Step-by-step 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* (23 g/mol)+(35.5 g/mol)* 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* (23 g/mol)+(35.5 g/mol)* 2]=2* [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* (23 g/mol)+(35.5 g/mol)* 2]=2* [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)* 2]=2* [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).