Co-ordination Compounds MCQs for NEET — Chemistry Questions with Answers

It is a method for refining of Al.

The cell used in this process consists of an iron tank lined with carbon at the bottom. A molten alloy of copper, crude aluminium and silicon is used as the anode. It forms the lowermost layer in the cell. The middle layer consists of molten mixture of fluorides of sodium, aluminium and barium (cryolite + BaF₂). The uppermost layer consists of molten aluminium. A set of graphite rods dipped in molten aluminium serve as the cathode. During electrolysis, Al³⁺ ions from the middle layer migrate to the upper layer, where they are reduced to aluminum by gaining 3 electrons. Equal numbers of Al³⁺ ions are produced in the lower layer. These ions migrate to the middle layer. Pure aluminium is tapped off from time to time. The Hoopes process gives about 99.99% pure aluminium.

It is an use of alum.

A mordant or dye fixative is a substance used to set (i.e. bind) dyes on fabrics by forming a coordination complex with the dye, which then attaches to the fabric (or tissue).^[1] It may be used for dyeing fabrics or for intensifying stains in cell or tissue preparations. Although mordants are still used, especially by small batch dyers, it has been largely displaced in industry by directs.^[2]

(d) Fe₄[Fe(CN)₆]₃ sol is Prussian blue sol of + ve charge.

(b) Mond's process is used for the purification of Ni.

(c) This is Van-Arkel method for purification of Ti.

(d) Ni(CO)₄ $\stackrel{∆}{\to }$ Ni + 4CO

(b) For purification of Ni in Mond's process.

(b) The reaction involved in cyanide extraction process are:

Ag₂S +4NaCN $\to$2Na[Ag(CN)₂]+Na₂S

4Na₂S + 5[O₂] + 2H₂O $\to$2Na₂SO₄ + 4NaOH + 2S

2Na[Ag(CN)₂]+ZN $\to$Na₂[Zn(CN)₄]+2Ag$\downarrow$

(b) Both Ag and Au are extracted by complex formation method