When $KMn{O}_4$ solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because

1.  $C{O}_2$ is formed as the product

2.  Reaction is exothermic

3.  $Mn{O}_4^{-}$ catalyses the reaction

4.  $M{n}^{2+}$ acts as autocatalyst

There are 14 elements in the actinoid series. Which of the following elements does not belong to this series?

1. U

2. Np

3. Tm

4. Fm

$KMn{O}_4$ acts as an oxidizing agent in an acidic medium. The number of moles of $KMn{O}_4$ that will be needed to react with one mole of sulphide ions in an acidic solution is$\mathrm{:}$
1. \(\frac{2}{5}\)
2. \(\frac{3}{5}\)
3. \(\frac{4}{5}\)
4. \(\frac{1}{5}\)

Which of the following is amphoteric oxide ?

$1. V_2{O}_5 , C{r}_2{O}_3$
$2. M{n}_2{O}_7 , Cr{O}_3$
$3. CrO , V_2{O}_5$
$4. V_2{O}_5 , V_2{O}_4$

Gadolinium (atomic number 64) belongs to the 4f series.
The correct electronic configuration of gadolinium among the following is:

\(1. (X e) 4 f^{7} 5 d^{1} 6 s^{2} \)

2. \( (X e) 4 f^{6} 5 d^{2} 6 s^{2}\)

3. \((X e) 4 f^{8} 6 d^{2}\)

4. \((X e) 4 f^{9} 5 s^{1}\)

Interstitial compounds are formed when small atoms are trapped inside the crystal lattice of metals. Which of the following is not the characteristic property of interstitial compounds? 
 

The magnetic moment is associated with its spin angular momentum and orbital angular momentum. Spin only magnetic moment value of $C{r}^{3+}$ ion is

1.  2.87 BM

2.  3.87 BM

3.  3.47 BM

4.  3.57 BM

 $KMn{O}_4 acts as an oxidi\sin g agent in alkaline$
$medium. When alkaline KMn{O}_4 is treated$
$with KI, iodide ion is oxidised to ......... .$
$$
$1. I_2$
$2. I{O}^{-}$
$3. I{O}_3^{-}$
$4. I{O}_4^{-}$

Which of the following statements is not correct?

1. Copper liberates hydrogen from acids

2. In its higher oxidation states, manganese forms stable compounds with oxygen and fluorine

3. $M{n}^{3+} and C{o}^{3+}$ are oxidising agents in an aqueous solution

4. $T{i}^{2+} and C{r}^{2+}$ are reducing agents in an aqueous solution

When acidified $K_{2}C{r}_2{O}_7$ the solution is added to Sn⁺⁺ salt then Sn⁺⁺ changes to

1. Sn
2. Sn³⁺
3. Sn⁴⁺
4. Sn⁺