Chapter 9

An important ore of magnesium is: (a) Malachite (b) Cassiterite (c) Carnalite (d) Galena

The most unstable carbonate is: (a) \(\mathrm{Cs}_{2} \mathrm{CO}_{3}\) (b) \(\mathrm{Li}_{2} \mathrm{CO}_{3}\) (c) \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) (d) \(\mathrm{K}_{2} \mathrm{CO}_{3}\)

Initial setting of cement is mainly due to: (a) Hydration and hydrolysis (b) Dehydration and gel formation (c) Dehydration and dehydrolysis (d) Hydration and gel formation

What are the products formed when \(\mathrm{Li}_{2} \mathrm{CO}_{3}\) undergoes decomposition? (a) \(\mathrm{LiO}_{2}+\mathrm{CO}\) (b) \(\mathrm{Li}_{2} \mathrm{O}+\mathrm{CO}\) (c) \(\mathrm{Li}_{2} \mathrm{O}_{2}+\mathrm{CO}\) (d) \(\mathrm{Li}_{2} \mathrm{O}+\mathrm{CO}_{2}\)

On heating sodium metal in a current of dry ammonia, the compound formed is: (a) Sodium hydride (b) Sodium amide (c) Sodium azide (d) Sodium nitride

Sodium nitrate decomposes above \(\sim 800^{\circ} \mathrm{C}\) to give: (a) \(\mathrm{N}_{2}\) (b) \(\mathrm{O}_{2}\) (c) \(\mathrm{NO}_{2}\) (d) \(\mathrm{Na}_{2} \mathrm{O}\)

What is the reaction occurring at the anode in Down? process for the extraction of sodium? (a) \(2 \mathrm{Cl}^{-} \rightarrow \mathrm{Cl}_{2}+2 \mathrm{e}^{-}\) (b) \(\mathrm{NaOH} \rightarrow \mathrm{Na}++\mathrm{OH}^{-}\) (c) \(4 \mathrm{OH}^{-} \rightarrow 2 \mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2}+4 \mathrm{e}^{-}\) (d) \(\mathrm{Na}^{+}+\mathrm{e}^{-} \rightarrow \mathrm{Na}\)

Magnesium can be obtained by: (a) Reducing magnesium salt solution with \(\mathrm{Fe}\) (b) Electrolysis of fused magnesium salt (c) Electrolysis of \(\mathrm{Mg}\left(\mathrm{NO}_{3}\right)_{2}\) solution (d) Reducing MgO with coke

The solubilities of carbonates decrease down the magnesium group due to a decrease in: (a) Inter ionic interaction (b) Lattice energies of solids (c) Entropy of solution formation (d) Hydration energies of cations

Magnesium does not decompose in: (a) Hot water (b) Steam (c) Semi - hot water (d) Cold water