Class 12th

(A) Concentration of Ag & Au done by NaCN. It is known as Mac Arthur Process (cyanide process)
(B) Blast furnace produces pig Fe.
(C) Blister Cu → Reverberatory furnace. In this furnace smelting & roasting of ore take place
CuFeS? + O? → Cu? O + FeO
(D) Froth floatation process is used for concentration of sulphide ores.

Polyamide copolymers are biodegradable polymers.
Polymers Nylon-2 Nylon-6 are polyamides and monomers of Nylon-2 nylon-6 are:
H? N–CH? –COOH (Glycine) & H? N– (CH? )? –COOH (Aminocaproic acid)

  Phase |            Medium |          Colloid Type |
| (1) Cheese |            liquid | solid |    Gel |
| (2) Pumice stone |  gas | solid |        Solid sol |
| (3) Hair cream |      liquid | liquid |    Emulsion |
| (4) Cloud | liquid |  gas | Aerosol |

Chelation increases stability of complex. Also more the chelation more the stability. Here, [Co (en)? (NH? )? ]Cl? , [Co (en)? ]Cl? and [Co (en) (NH? )? ]Cl? have chelation due to ethylenediamine. Therefore [Co (en)? ]Cl? has the highest chelation so the highest stability.

Using, µ = √n (n+2) B.M, n = number of unpaired electrons.
? Ti? ³ = 4s? 3d¹, unpaired electron = 1
µ = 1.73 B.M
? V? ² = 4s? 3d³, unpaired electron = 3
µ = 3.87 B.M
? Sc? ³ = 4s? 3d? , unpaired electron = 0
µ = 0 B.M

Heating of cis-but-2-enedioic acid gives maleic anhydride as shown.
[Chemical reaction showing conversion of cis-but-2-enedioic acid to maleic anhydride upon heating]

A = A? (1/2)?
A/A? = 1/8 = (1/2)³ ⇒ n = 3
t = n T½
30 = 3 T½
T½ = 10 years