5
MCQ (Single Correct Answer)
Which of the carbonates given below is unstable in air and is kept in $\mathrm{CO}_2$ atmosphere to avoid decomposition?
A
$\mathrm{BeCO}_3$
B
$\mathrm{MgCO}_3$
C
$\mathrm{CaCO}_3$
D
$\mathrm{BaCO}_3$
6
MCQ (Single Correct Answer)
Metals form basic hydroxides. Which of the following metal hydroxide is the least basic?
A
$\mathrm{Mg}(\mathrm{OH})_2$
B
$\mathrm{Ca}(\mathrm{OH})_2$
C
$\mathrm{Sr}(\mathrm{OH})_2$
D
$\mathrm{Ba}(\mathrm{OH})_2$
7
MCQ (Single Correct Answer)
Some of the Group 2 metal halides are covalent and soluble in organic solvents. Among the following metal halides, the one which is soluble in ethanol is
A
$\mathrm{BeCl}_2$
B
$\mathrm{MgCl}_2$
C
$\mathrm{CaCl}_2$
D
$\mathrm{SrCl}_2$
8
MCQ (Single Correct Answer)
The order of decreasing ionisation enthalpy in alkali metals is
A
$\mathrm{Na}>\mathrm{Li}>\mathrm{K}>\mathrm{Rb}$
B
$\mathrm{Rb}<\mathrm{Na}<\mathrm{K}<\mathrm{Li}$
C
$\mathrm{Li}>\mathrm{Na}>\mathrm{K}>\mathrm{Rb}$
D
$\mathrm{K}<\mathrm{Li}<\mathrm{Na}<\mathrm{Rb}$
9
MCQ (Single Correct Answer)
The solubility of metal halides depends on their nature, lattice enthalpy and hydration enthalpy of the individual ions. Amongst fluorides of alkali metals, the lowest solubility of LiF in water is due to
A
ionic nature of lithium fluoride
B
high lattice enthalpy
C
high hydration enthalpy for lithium ion
D
low ionisation enthalpy of lithium atom