Question

In a chemical reaction, a certain amount of hydrochloric acid reacts with 10 grams of sodium hydroxide to produce 19 grams of a solution containing sodium chloride and water. Which statement is correct? The mass of water formed is 29 grams. The mass of sodium chloride formed is 29 grams. The total mass of hydrochloric acid used is 10 grams. The total mass of hydrochloric acid used is less than 10 grams.

Answer 1

Answer: The total mass of hydrochloric acid used is less than 10 grams.

Explanation:

According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

$HCl+NaOH\rightarrow NaCl+H_2O$

Given: mass of sodium hydroxide = 10 g

Mass of products = Mass of sodium chloride + mass of water = 29 grams

Thus mass of reactant = mass  of hydrochloric acid + mass of sodium hydroxide= 29 g

Mass of hydrochloric acid + 10 g = 19 g

Mass of hydrochloric acid = 9 g

Thus the total mass of hydrochloric acid used is less than 10 grams.

Answer 2

D, The total mass of hydrochloric acid used is less than 10 grams.

Conservation of mass, matter cannot be created or destroyed.