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9
MCQ (Single Correct Answer)

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

A
$\mathrm{CO}_2$ is formed as the product
B
reaction is exothermic
C
$\mathrm{MnO}_4^{-}$catalyses the reaction
D
$\mathrm{Mn}^{2+}$ acts as autocatalyst
10
MCQ (Single Correct Answer)

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

A
U
B
Np
C
Tm
D
Fm
11
MCQ (Single Correct Answer)

$\mathrm{KMnO}_4$ acts as an oxidising agent in acidic medium. The number of moles of $\mathrm{KMnO}_4$ that will be needed to react with one mole of sulphide ions in acidic solution is

A
$\frac{2}{5}$
B
$\frac{3}{5}$
C
$\frac{4}{5}$
D
$\frac{1}{5}$
12
MCQ (Single Correct Answer)

Which of the following is amphoteric oxide?

$$\mathrm{Mn}_2 \mathrm{O}_7, \mathrm{CrO}_3, \mathrm{Cr}_2 \mathrm{O}_3, \mathrm{CrO}, \mathrm{~V}_2 \mathrm{O}_5, \mathrm{~V}_2 \mathrm{O}_4$$

A
$\mathrm{V}_2 \mathrm{O}_5, \mathrm{Cr}_2 \mathrm{O}_3$
B
$\mathrm{Mn}_2 \mathrm{O}_7, \mathrm{CrO}_3$
C
$\mathrm{CrO}, \mathrm{V}_2 \mathrm{O}_5$
D
$\mathrm{V}_2 \mathrm{O}_5, \mathrm{~V}_2 \mathrm{O}_4$
13
MCQ (Single Correct Answer)

Gadolinium belongs to 4 f series. Its atomic number is 64 . Which of the following is the correct electronic configuration of gadolinium?

A
$[\mathrm{Xe}] 4 f^7 5 d^1 6 s^2$
B
$[\mathrm{Xe}] 44^6 5 d^2 6 s^2$
C
$[\mathrm{Xe}] 4 f^8 6 d^2$
D
$[\mathrm{Xe}] 4 f^9 5 s^1$
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