Question

Arrange the following compounds in the increasing orders of their melting point.
$\text{I}.BaC{l}_2$ $\text{II}.SrC{l}_2$ $\text{III}.CaC{l}_2$ $\text{IV}.MgC{l}_2$ $\text{V}.BeC{l}_2$

• A. $III<V<I<II<IV$
• B. $V<IV<II<I<III$
• C. $V<IV<III<II<I$
• D. $I<III<V<II<IV$

Answer 1

The correct option is C $V<IV<III<II<I$

All the compounds have $C{l}^{-}$ anion, we have to check the size of the cation. Higher the size of the cation, lesser will be covalent chararcter which results increase in melting point.
Order of decrease in melting point will be,
$\underset{{960}^{o}C}{BaC{l}_2}>\underset{{872}^{o}C}{SrC{l}_2}>\underset{{772}^{o}C}{CaC{l}_2}>\underset{{712}^{o}C}{MgC{l}_2}>\underset{{405}^{o}C}{BeC{l}_2}$