You visited us 1 times! Enjoying our articles? Unlock Full Access!

Byju's Answer

Standard XII

Chemistry

Assigning Oxidation Numbers

12.5 ml of ...

Question

$12.5 m l$ of $0.05 M S e O_{2}$ oxidised $25 m l$ of $0.3 M C r S O_{4}$ solution to $C r_{2} (S O_{4})_{3}$ . What is the final oxidation number of $S e$ ?

+ 2

No worries! We‘ve got your back. Try BYJU‘S free classes today!

+ 4

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

+ 6

No worries! We‘ve got your back. Try BYJU‘S free classes today!

0

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is B $+ 4$
The reaction is-
${S e}^{4 +} + 4 e \to {S e}^{0}$
Chromium is oxidized, which means it has lost some electrons. Therefore it is a reducing agent. If the original assumption was right 1 Se for every 4 Cr, then we can assume that 4 electrons are lost for every 1 Se. Assuming that the original oxidation state of Se was 4+ we can say that the oxidation state for Se is now 0.
Hence answer is option B

Suggest Corrections

Similar questions

Q. 12.5 ml of 0.05 M

S e O_{2}

reacts with 25 ml of 0.1 M

C r S O_{4}

which is oxidised to

C r^{3 +}

. To what oxidation state was the selenium converted by the reaction?

Q. What is the

p H

of a solution in which

25 mL

0.1 M N a O H

is added to

25 mL

0.08 M H C l

and final solution is diluted to

500 mL ?

{M n O_{4}}^{-}

ions are reduced in acidic condition to

M n^{2 +}

ions whereas they are reduced in neutral condition to

M n O_{2}

. The oxidation of

25 m L

of a solution

X

containing

F e^{2 +}

ions required in acidic condition,

20 m L

of a solution

Y

containing

{M n O_{4}}^{-}

ions. What volume of solution

Y

would be required to oxidise

25 m L

of solution

X

containing

F e^{2 +}

ions in neutral condition?

Q. An impure sample of

A s_{2} O_{3}

weighing

20 g m

was dissolved in water containing

10 g m o f N a H C O_{3}

and the final solution was diluted to

400 m L

20 m L

of this solution was oxidised by

25 m L

of a solution of

I_{2}

. Another solution of hypo containing

1.24 g m

N a_{2} S_{2} O_{3} .5 H_{2} O

40 m L

was used to exactly reduce

25 m L

of same

I_{2}

solution (impurities inert) calculate % of

A s_{2} O_{3}

in the sample (at. wt. of As = 75)

12 g

of an impure sample of arsenious oxide was dissolved in water containing

7.5 g

of sodium bicarbonate and the resulting solution was diluted to

250 m L

25 m L

of this solution was completely oxidised by

22.4 m L

of a solution of iodine.

25 m L

of this iodine solution reacted with same volume of a solution containing

24.8 g

of sodium thiosulphate solution

(N a_{2} S_{2} O_{3} \cdot 5 H_{2} O)

in one litre. Calculate the percentage of arsenious oxide in the sample. (Atomic mass of

A s = 75)

Join BYJU'S Learning Program

12.5 ml of 0.05 M SeO2 oxidised 25 ml of 0.3 M CrSO4 solution to Cr2(SO4)3. What is the final oxidation number of Se ?

$12.5 m l$ of $0.05 M S e O_{2}$ oxidised $25 m l$ of $0.3 M C r S O_{4}$ solution to $C r_{2} (S O_{4})_{3}$ . What is the final oxidation number of $S e$ ?