--%>
Assignment Help - homework help

  Properties of Potassium dichromate

Properties of Potassium dichromate:

Physical properties:

1. It made orange red crystals that melt at 396°C.

2. It is fairly soluble in cold water and however freely soluble in hot water.

Chemical properties:

1. Action of Heat:

On heating, K2Cr2O7 decomposes to provide potassium chromate with the evolution of O2 gas.

4K2Cr2O7 → 4K2CrO4 + 2Cr2O3 + 3O2

2. With Alkalies:

Whenever an alkali is added to an orange-red solution of K2Cr2O7, a yellow solution outcomes due to the formation of potassium chromate.

K2Cr2O7 + 2KOH → 2K2CrO4 + H2O
Orange-red                Yellow

On acidifying the yellow color of K2CrO4 again alters to orange red due to the reformation of K2Cr2O7.

2K2CrO4 + H2SO4 → K2Cr2O7 + K2SO4 + H2O
                              Orange red

The inter conversion is demonstrated on the basis of the fact that in K2Cr2O7 solution, orange red Cr2O72- ions are in symmetry with yellow CrO42- ions.

Cr2O72- + H2O ↔ 2CrO42- + 2H+
Orange red           Yellow

3. Oxidising properties:

K2Cr2O7 is a powerful oxidising agent. In the presence of dilute H2SO4, one mole of this compound provides three atoms of oxygen as illustrated below.
K2Cr2O7 + 4 dil.H2SO4 → K2SO4 + Cr2(SO4)3 + 4H2O + 3(O)

4. Chromyl chloride test:

Whenever salt having chloride is treated with K2Cr2O7 and concentrated H2SO4 reddish brown vapors of chromyl chloride are acquired.

K2Cr2O7 + 4KCl + 6H2SO4 → 2CrO2Cl2 + 6 KHSO4 + 3H2O
                                           Chromylchloride

This reaction is utilized in the detection of chloride ions in qualitative analysis.

 

Latest technology based Chemistry Online Tutoring Assistance

Tutors, at the www.tutorsglobe.com, take pledge to provide full satisfaction and assurance in D Block Elements homework help via online tutoring. Students are getting 100% satisfaction by online tutors across the globe. Here you can get homework help for D Block Elements, project ideas and tutorials. We provide email based D Block Elements homework help. You can join us to ask queries 24x7 with live, experienced and qualified online tutors specialized in D Block Elements. Through Online Tutoring, you would be able to complete your homework or assignments at your home. Tutors at the TutorsGlobe are committed to provide the best quality online tutoring assistance for Inorganic-Chemistry Homework Help and assignment help services. They use their experience, as they have solved thousands of the Chemistry assignments, which may help you to solve your complex issues of D Block Elements. TutorsGlobe assure for the best quality compliance to your homework. Compromise with quality is not in our dictionary. If we feel that we are not able to provide the homework help as per the deadline or given instruction by the student, we refund the money of the student without any delay.