+91-8076753736 support@wiredfaculty.com

Sponsor Area

The D-And-f-Block Elements

Question

Wired Faculty App

What happens when chromates are kept in acidic solution and dichromate in alkaline solution?

Solution

When a chromium (III) salt is heated in alkaline solution with a peroxide a chromate (VI) ion is formed.

2Cr³⁺(aq) +4OH^-(aq)+3O₂^2-(aq) ---> 2CrO₄^2- (aq)+2H₂O(l)

The Cr³⁺ (aq) ion is blue -violet the CrO₄^2- (aq) ion yellow.

In acid solution yellow chrmoateVI ions Condense to form orange dichromate(VI) ion.

2CrO₄^2- (aq) +2H⁺ (aq) ---> Cr₂O₇^2-(aq) +2H₂O(l)

Some More Questions From The d-And-f-Block Elements Chapter

Silver atom has a completely filled d orbitals (4d¹⁰) in its ground state. How can you say that it is a transition element?

In the series Sc (Z = 21) to Zn(Z = 30), the enthalpy of atomisation of zinc is the lowest i.e., 26, kJ mol. Why?

The E° (M²⁺/M) value for copper is positive (+ 0.34 V). What is possibility the reason for this?

How would you account for the irregular variation of ionisation enthalpies (first and second) in the first series of the transition elements?

Why is the highest oxidation state of a metal exhibited in its oxide or fluoride only?

Which is a stronger reducing agent Cr²⁺ or Fe²⁺ and why?

Explain why Cu⁺ ion is not stable in aqueous solutions?

Actinoid contraction is greater from element to element than lanthanoid contraction. Why?

On what ground can you say that scandium (Z = 21) is a transition element but zinc (Z = 30) is not?

Mock Test Series

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation