KMnO₄ can be prepared from K₂MnO₄ as per the reaction: 
$3{\mathrm{MnO}}_4^{2-}+2{\mathrm{H}}_2\mathrm{O}\rightleftharpoons 2{\mathrm{MnO}}_4^{-}+{\mathrm{MnO}}_2+4{\mathrm{OH}}^{-}$
The reaction can go to completion by removing OH^– ions by adding:

1. KOH
2. CO₂
3. SO₂
4. HCl

 

Identify the alloy containing a non-metal as a constituent in it.

1. Invar

2. Steel

3. Bell metal

4. Bronze

1.  Fe>Mn>Co>Cr

2.  Co>Mn>Fe>Cr

3.  Cr>Mn>Co>Fe

4.  Mn>Fe>Cr>Co

The acidified \(\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7\) solution turns green when \(\mathrm{Na}_2 \mathrm{SO}_3\) is added to it. This is due to the formation of:

A colored ion in aqueous solutions among the following is:

1. La³⁺ (Z=57)

2. Ti³⁺ (Z=22)

3. Lu³⁺ (Z=71)

4. Sc³⁺ (Z=21)

The species that are colourless:

(Z of Ti = 22, Co=27, Cu = 29, Ni= 28)

1. ${\mathrm{TiF}}_6^{2-}$ $\mathrm{and}$ ${\mathrm{CoF}}_6^{3-}$

2. ${\mathrm{Cu}}_2{\mathrm{Cl}}_2$ $\mathrm{and}$ ${\mathrm{NiCl}}_4^{2-}$

3. ${\mathrm{TiF}}_6^{2-}$ $\mathrm{and}$ ${\mathrm{Cu}}_2{\mathrm{Cl}}_2$

4. ${\mathrm{CoF}}_6^{3-}$ $\mathrm{and}$ ${\mathrm{NiCl}}_4^{2-}$

The incorrect statement among the following is:  

Which one of the following ions is the most stable in aqueous solution? 
(At. No. Ti = 22, V = 23, Cr = 24, Mn = 25)

1. $C{r}^{3+}$

2. $V^{3+}$

3. $T{i}^{3+}$

4. $M{n}^{3+}$

In which of the following pairs are both the ions coloured in aqueous solution? 
(At. no. : Sc = 21, Ti = 22, Ni = 28, Cu = 29, Co= 27)

1. $N{i}^{2+}, T{i}^{3+}$

2. $S{c}^{3+}, T{i}^{3+}$

3. $S{c}^{3+}, C{o}^{2+}$

4. $N{i}^{2+}, C{u}^{+}$