Chapter 18, Problem 83E

(a)

Interpretation Introduction

Interpretation: The difference in the reactivity of $\text{AgCl}$ in lenses and as pure silver chloride needs to be explained.

Concept Introduction:

Metals make the 75 % part of the periodic table. Metals are electropositive elements and mainly form ionic compound whereas non-metals are electronegative elements and can form either covalent or ionic compounds.

Halogens are most electronegative non-metals which are placed in the group-7 A. Due to more electronegative nature, they mainly forms ionic or covalent compounds with metals. These compounds are called as halides.

(b)

Interpretation Introduction

Interpretation: The reason of permanent darkness in the photo gray lenses needs to be explained.

Concept Introduction:

Metals make the 75 % part of the periodic table. Metals are electropositive elements and mainly form ionic compound whereas non-metals are electronegative elements and can form either covalent or ionic compounds.

Halogens are most electronegative non-metals which are placed in the group-7 A. Due to more electronegative nature, they mainly forms ionic or covalent compounds with metals. These compounds are called as halides.