1
MCQ (Single Correct Answer)
The alkali metals are low melting. Which of the following alkali metal is expected to melt if the room temperature rises to $30^{\circ} \mathrm{C}$ ?
A
Na
B
K
C
Rb
D
Cs
2
MCQ (Single Correct Answer)
Alkali metals react with water vigorously to form hydroxides and dihydrogen. Which of the following alkali metals reacts with water least vigorously?
A
Li
B
Na
C
K
D
Cs
3
MCQ (Single Correct Answer)
The reducing power of a metal depends on various factors. Suggest the factor which makes Li, the strongest reducing agent in aqueous solution.
A
Sublimation enthalpy
B
lonisation enthalpy
C
Hydration enthalpy
D
Electron-gain enthalpy
4
MCQ (Single Correct Answer)
Metal carbonates decompose on heating to give metal oxide and carbon dioxide. Which of the metal carbonates is most stable thermally?
A
$\mathrm{MgCO}_3$
B
$\mathrm{CaCO}_3$
C
$\mathrm{SrCO}_3$
D
$\mathrm{BaCO}_3$
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
$\mathrm{BaCO}_3$