Correct Answer: A. Aufbau Principle

Correct Answer: B. Hybridization of orbitals

Explanation

- An atom may give, take, or share electrons with another atom to achieve a full valence shell, the most stable electron configuration.

- Hybrid orbitals are useful in the explanation of molecular geometry and atomic bonding properties and are symmetrically disposed in space.

Correct Answer: C. Crystallization would be efficient in separating out a salt whose solubility increases considerably with temperature

Explanation

Crystallization is based on the principles of solubility: compounds (solutes) tend to be more soluble in hot liquids (solvents) than they are in cold liquids. If a saturated hot solution is allowed to cool, the solute is no longer soluble in the solvent and forms crystals of pure compound.

Correct Answer: B. smaller atomic size

Explanation

- Magnessium has a stronger metallic bond than calcium because it has smaller atomic radius.

- Atomic radius decreases across a period and increases down a group.

Correct Answer: A. Calcium trioxocarbonate ( iv ) chips a 20°C

Correct Answer: B. 5.4 x 10^-3

Explanation

No. of moles = ( molar conc X volume ) / 1000

No. of moles = 0.108 X 50 / 1000

: No. of moles = 0.0054 moles

Correct Answer: C. Protein

Correct Answer: A. Copper

Explanation

Most alkali metals and alkaline earth metals react with water to produce hydrogen. The alkali metals comprise Group 1 of the periodic table, and include lithium, sodium, potassium, etc.

- Zinc is not much reactive with cold or room temperature water but reacts with steam to form zinc oxide and liberate hydrogen gas.

- Copper lies below hydrogen in the activity series of metals, therefore it can not displace hydrogen from water

Correct Answer: B. I and III only

Explanation

(a)(i) ammonia: - hydrogen chloride: - sulphur (iv) Oxide (ii) To demonstrate high/extreme solubility of gases HCl / NH\(_3\) / SO\(_2\) in water.

(iii) A flask. fitted with a glass jet is filled with dry ammonia or any soluble gas. Inject water through the inlet into the flask. this dissolves the ammonia soluble gas and causes a fountain through the jet.

OR

-a round bottomed flask is filled with gas and fitted with two delivery tubes and closed by use of clips A and B; - Invert the flask into a beaker of water: - open a clip A to allow small volume of water to enter the flask. then close it - the gas dissolves in water causing sudden reduction of pressure in the flask: open clip B: reduced gas pressure causes water from the beaker through delivery tube into the flask forming fountain.

(b) (i)-Textiles: Tannery: - Brewery Bottling company: Soaps and detergents: - food industry: pharmaceuticals: - cosmetics: petrochemical Industry: - petroleum industry; dyes: paints; agrochemicals: fertilizers; - pesticides; plastic

(ii) Improvement in the standard of living of people: - employment opportunities: - development in the community: pollution (air. land. water. etc.)

(c) (i) - coke; - coal tar; - coal gas: ammoniacal liquor

(ii) Coke (solid) fuel production of water gas extraction of metals. Coal tar; synthesis of chemicals.perfumes dyes/paints / drugs / plastics explosives / tanning of roads. Coal gas; as fuel (in homes and industries). Ammoniacal liquor;- production of fertilizer

(d)i) calcium hydrogen trioxocarbonate (IV): -calcium tetraoxosulphate (Vi): - magnesium tetraoxosulphate (Vi)

- magnesium hydrogen trioxocarbonate (IV); - iron (III) chloride.

(ii)heating the water to boiling / distillation: addition of calculated amount of calcium hydroxide: - addition of washing soda crystals: - ion exchange resin permutit

(iii)- calcium ions in the water are good for method children's teeth and bones: it helps to reduce heart diseases; does not dissolve lead pipes: - tastes better than soft water:- provides calcium salts used in manufacturing of food in plants: production of exoskeleton of animals / shells Tannery: