Question

Give the formula and valency of chromate.

Answer 1

Hint: Chromate is generally oxoanion which formed by the removal of protons from chromic acid. It is also known by the name chromium oxoanion or divalent inorganic anions. Sodium and potassium salts are the most commonly used chromate salts.

Complete Solution :
Chromate is generally found as yellow powder which is odorless and it is generally soluble in water. In acidic solutions chromate ions acts as a strong oxidizing agent while in alkaline or basic solution chromate ion combines with water to form chromium hydroxide showing oxidation state of +3 and chromate as its potassium salt reacts with barium nitrate forms barium chromate and potassium nitrate.
Chromate are the salts of chromic acid which contain chromate ion represented by the formula \[Cr{{O}_{4}}^{2-}\]and usually found in intense yellow color powder. The oxidation state shown by chromate ion is +6 and Valency of atoms is defined as the combining capacity of an atom. The number of bonds that an atom can form as part of a compound is said to be the valency of the element. Valence electrons are those electrons which are present in the outermost shell of an atom. In case of chromate the valency shown by the chromium is 2.
Hence the formula of chromate ion is \[Cr{{O}_{4}}^{2-}\] and valency is 2.

Note: Chromate is mainly used as an inhibitor for corrosion in which it is used as a primer, decorative finish or also used to maintain electrical conductance and can also be used in preparing children’s crayons as it is non-toxic in nature.