which are the most important reactions that one should surely know in d-block elements?

Hi,

Important reaction from d-block elements are as follows:

It is prepared by fusion of chromate ore (FeCr₂O₄) with sodium carbonate in excess of air.

4FeCr₂O₄ + 8Na₂CO₃ + 7O₂   8Na₂CrO₄ + 2Fe₂O₃ + 8CO₂ 

2Na₂CrO₄ + H₂SO₄ Na₂Cr₂O₇ + H₂O + Na₂SO₄

Sodium                                Sodium

chromate                             dichromate

Na₂Cr₂O₇ + 2KCl K₂Cr₂O₇ + 2NaCl

Effect of pH on chromate and dichromate ions: The chromates and dichromates are interconvertible in aqueous solution depending upon pH of the solution. The oxidation state of chromium in chromate and dichromate is the same

2 CrO₄^2- + 2H⁺   Cr₂O₇^2- + H₂O

Cr₂O₇^2- + 2 OH- 2 CrO₄^2-+ H₂O

1. Potassium dichromate acts as a strong oxidizing agent in acidic medium.

Cr₂O₇^2- +14 H⁺ + 6e^- 2 Cr³⁺ + 7 H₂O

1. Potassium permanganate acts as a strong oxidizing agent in acidic, neutral or faintly basic medium.

In acidic medium.

MnO₄^- + 8 H⁺ + 5 e^- Mn²⁺ + 4 H₂O

In neutral or faintly basic medium,

MnO₄^- + 3 e^- + 2 H₂O MnO₂ + 4OH^-