Calcination

Q.

Consider The Following Transformation:

1. ${\mathrm{XeF}}_6+\mathrm{NaF}\to {\mathrm{Na}}^{+}{\left[{\mathrm{XeF}}_7\right]}^{-}$
2. $2{\mathrm{PCl}}_5\left(\mathrm{s}\right)\to {\left[{\mathrm{PCl}}_4\right]}^{+}{\left[\mathrm{PCl}6\right]}^{-}$
3. $[\mathrm{Al}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6{]}^{3+}+{\mathrm{H}}_2\mathrm{O}\to [\mathrm{Al}{\left({\mathrm{H}}_2\mathrm{O}\right)}_5\mathrm{OH}{]}^{2+}+{\mathrm{H}}_3{\mathrm{O}}^{+}$

Possible Transformations Are:

1. 1 and 2

2. 1 and 3

3. 2 and 3

4. 1, 2, and 3

Q.

15. Generally, a metal gets corroded due to oxidation. Name a metal which becomes chemically resistant due to oxidation.

1. zinc

2. copper

3. aluminium

4. iron

Q.

Which one of the following processes makes the ore porous?

1. Froth floatation

2. Smelting

3. Calcination

4. Distillation

Q. Copper sulphate dissolved in excess of $KCN$ to give:-

1. $CuCN$
2. $\left[Cu\right(CN{)}_4{]}^3$
3. $\left[Cu\right(CN{)}_4{]}^2$
4. $Cu(CN{)}_2$

Q. Calcination is a process in which the ore is heated strongly in the absence of air to remove volatile impurities. It thermally decomposes the carbonate.
$2F{e}_2{O}_3.3H_{2}O\stackrel{Calcination}{\to }A+3H_{2}O$
Find out $A$:

1. $2FeO$
2. $2F{e}_3{O}_4$
3. $2F{e}_2{O}_3$
4. $FeO.FeC{O}_3$

Q.

why silver does not rust if we keep it outside many days than in iron?

Q.

Which of the following reactions could be termed as calcination?

1. CaCO₃ → CaO + CO₂

2. 4FeS₂ + 11O₂→ 2Fe₂O₃ + 8SO₂

3. 2 Al(OH)₃→ Al₂O₃ + 3H₂O

4. CuS + CuSO₄ → 2Cu + 2SO₂