Question

If $$KMn{O_4}$$   is reduced by oxalic acid in an acidic medium then oxidation number of $$Mn$$  changes from

A. 4 to 2
B. 6 to 4
C. +7 to +2  
D. 7 to 4
Answer :   +7 to +2
Solution :
In acid medium
$$MnO_4^ - + 8{H^ + } + 5{e^ - } \to M{n^{2 + }} + 4{H_2}O$$
( $$O.S.$$  of $$Mn$$  changes form +7 to +2 ).

Releted MCQ Question on
Inorganic Chemistry >> D and F Block Elements

Releted Question 1

When same amount of zinc is treated separately with excess of sulphuric acid and excess of sodium hydroxide, the ratio of volume of hydrogen evolved is

A. $$1:1$$
B. $$1:2$$
C. $$2:1$$
D. $$9:4$$
Releted Question 2

Which of the following is the weakest base

A. $$NaOH$$
B. $$Ca{\left( {OH} \right)_2}$$
C. $$KOH$$
D. $$Zn{\left( {OH} \right)_2}$$
Releted Question 3

One of the constituent of German silver is

A. $$Ag$$
B. $$Cu$$
C. $$Mg$$
D. $$Al$$
Releted Question 4

Which of the following dissolve in hot conc.$$NaOH$$  solution

A. $$Fe$$
B. $$Zn$$
C. $$Cu$$
D. $$Ag$$

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D and F Block Elements


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