Chapter 21, Problem 26PS

(a)

Interpretation Introduction

Interpretation: To write the balanced chemical equation of the reaction of formation of calcium hydride from calcium and $H_2$

Concept introduction: The reaction of elements with hydrogen produces either ionic metal hydrides or molecular compounds.  The reaction of hydrogen with metals produces ionic metal hydrides. The electronegativity of hydrogen is more than metals and hence, metals bear positive charge and hydrogen has a negative charge. Thus, the oxidation number of hydrogen in ionic metal hydrides is $-1$.

The reaction of calcium and hydrogen forms calcium hydride. The reaction occurs at $300-400$ degrees temperature. Calcium hydride is very reactive compound and reacts violently with water to produce hydrogen gas and calcium hydroxide. Thus, it is used as a drying agent for organic solvents. The hydrogen and calcium hydroxide is separated by the process of filtration or distillation.

(b)

Interpretation Introduction

Interpretation: To write the balanced chemical equation of the reaction of calcium hydride with water.

Concept introduction: The reaction of elements with hydrogen produces either ionic metal hydrides or molecular compounds.  The reaction of hydrogen with metals produces ionic metal hydrides. The electronegativity of hydrogen is more than metals and hence, metals bear positive charge and hydrogen has a negative charge. Thus, the oxidation number of hydrogen in ionic metal hydrides is $-1$.

The reaction of calcium and hydrogen forms calcium hydride. The reaction occurs at $300-400$ degrees temperature. Calcium hydride is very reactive compound and reacts violently with water to produce hydrogen gas and calcium hydroxide. Thus, it is used as a drying agent for organic solvents. The hydrogen and calcium hydroxide is separated by the process of filtration or distillation.