Question

In the chemical reaction shown below, the mass of water formed is _______.

Acid + Base $\to$ Salt + Water
35 g 40 g 57 g ?

• A. 24.5
• B. 16.25
• C. 18
• D. 20

Answer 1

The correct option is C 18

According to the law of conservation of mass, the total mass of the reactants is equal to the total mass of the products.

Mass of reactants = Mass of acid + mass of base
$⟹$ 35 + 40 = 75 g

Let the mass of the water formed be X grams.

The total mass of the products = Mass of salt + mass of water = (57 + X) g
On equating the mass of reactants with that of products, we get,
57 + X = 75 $⟹$ X = 18 g

Hence, the mass of water formed in the reaction is 18 g.