Chemistry 2014-2015 HSC Science (General) 12th Standard Board Exam Question Paper Solution

The hybridisation of phosphorus in phosphorus pentachloride is _______.

(A) dsp³

(B) sp³ d

(C) d² sp³

(D) sp³ d²

The rate constant for a first order reaction is 100 s^–1. The time required for completion of 50% of reaction is _______.

(A) 0.0693 milliseconds

(B) 0.693 milliseconds

(C) 6.93 milliseconds

(D) 69.3 milliseconds

Silica is added to roasted copper ore during smelting process to remove _______.

(A) ferrous sulphide

(B) ferrous oxide

(C) cuprous sulphide

(D) cuprous oxide

96500 coulombs correspond to the charge on how many electrons?

1.6 X 10¹⁹

6.022 X 10²⁰

6.022 X 10²³

6.022 X 10²⁴

For the reaction: Cl₂(g) → 2Cl(g), _______.

(A) ΔH is positive, ΔS is positive

(B) ΔH is positive, ΔS is negative

(C) ΔH is negative, ΔS is negative

(D) ΔH is negative, ΔS is positive

The substance ‘X’, when dissolved in solvent water gave molar mass corresponding to the molecular formula ‘X3’. The van’t Hoff factor (i) is _______.

(A) 3

(B) 0.33

(C) 1.3

(D) 1

The relation a ≠ b ≠ c and α ≠  β ≠  γ represents which crystal system?

(A) Orthorhombic

(B) Tetragonal

(C) Triclinic

(D) Monoclinic

Define ebullioscopic constant. Write its unit.

Answer the following in one or two sentences.

State second law of thermodynamics in terms of entropy.

State Third law of thermodynamics. Give ‘two’ uses.

What is the hybridisation of carbon atom in diamond and graphite?

0.1 mole of Buckminster fullerene contains how many kg of carbon? [Atomic mass of carbon = 12]

Draw structure of Chlorine trifluoride

Draw structure of Chlorine pentafluoride

Derive an expression for maximum work in isothermal reversible expansion of two moles of an ideal gas.

Can copper sulphate solution be stored in an iron vessel? Explain.

Define Average rate of reaction.

Define  Instantaneous rate of reaction.

Define Hydrometallurgy?

Define Electrometallurgy?

What is the action of dioxygen on Calcium

What is the action of dioxygen on Iron

What is the action of dioxygen on Carbon disulfide

A solution of glucose in water is labelled as 10% (W/W).

Calculate:

a. Molality

b. Molarity of the solution.

[Given: Density of solution is 1.20 g mL^-1 and molar mass of glucose is 180 g mol^-1 ]

Resistance of conductivity cell filled with 0.1 M KCl solution is 100 ohms. If the resistance of the same cell when filled with 0.02 M KCl solution is 520 ohms, calculate the conductivity and molar conductivity of 0.02 M KCl solution. [Given: Conductivity of 0.1 M KCl solution is 1.29 S m^-1 .]

Ammonia and oxygen react at high temperature as:

4NH_3(g) + 5O_2(g) → 4NO_(g) + 6H₂O_(g) In an experiment, rate of formation of NO_(g) is 3.6 x 10^-3 mol L^-1 s ^-1.

Calculate:

a. Rate of disappearance of ammonia.

b. Rate of formation of water.

What is the effect of temperature on solubility of a gas in a liquid?

Explain refining of nickel by Mond process.

State Kohlrausch’s law of independent migration of ions.

Silver crystallises in F.C.C. (face-centred cubic crystal) structure. The edge length of the unit cell is found to be 408.7 pm. Calculate density of the unit cell.

[Given: Molar mass of silver is 108 g mol^-1 ]

Write ‘four’ uses of hydrochloric acid.

Write chemical formula of the following oxoacids of chlorine:

a. Hypochlorous acid

b. Chlorous acid

c. Chloric acid

d. Perchloric acid

The equilibrium constant Kp for the reaction,

H_2(g) + I_2(g) → 2HI_(g) is 130 at 510 K. Calculate ΔG^o for the following reaction at the same temperature: 2HI_(g) → H_2(g) + I_2(g) [Given: R = 8.314 J K^-1 mol^-1 ]

Which among the following reducing agents is NOT used to reduce acetaldehyde to ethyl alcohol?

(A) Na-Hg and water

(B) Zn-Hg and conc. HCl

(C) H2-Raney Ni

(D) LiAlH4/H+

Acetaldehyde, when treated with which among the following reagents does NOT undergo addition reaction?

(A) Ammonia

(B) Hydroxylamine

(C) Ammoniacal silver nitrate

(D) Semicarbazide

What is natural rubber?

(A) Cis-1,4-polyisoprene

(B) Neoprene

(C) Trans-1,4-polyisoprene

(D) Butyl rubber

What is salvarsan?

(A) An antiseptic

(B) An antibiotic

(C) An antifertility drug

(D) An analgesic

Which among the following vitamins is also known as riboflavin?

(A) B1

(B) B2

(C) B6

(D) B12

The amine which reacts with nitrous acid to give yellow oily compound is _______.

(A) ethylamine

(B) isopropylamine

(C) secondary butylamine

(D) dimethylamine

What is the molecular formula of chromyl chloride?

(A) CrO₂Cl₂

(B) CrOCl₂

(C) CrCl₃

(D) Cr₂OCl₂

Identify ‘A’ and ‘B’ in the following reaction :

\[\ce{CH3 - CH = CH2 ->[HBr]'A' ->[alc.KOH]'B'}\]

Distinguish between lanthanoid and actinoids.

How are the following compounds prepared?

Benzyl alcohol from benzyl chloride.

How are the following compounds prepared?

Propan-1-ol from propanal

What is the action of acetic anhydride on ethylamine?

What is the action of acetic anhydride on diethylamine?

What are monosaccharides?

Draw ring structure of α - D - (+) - glucopyranose.

Explain Tranquilizers

Explain cationic detergents.

What is Stephen reaction?

Explain Sidgwick’s electronic theory with suitable example

What is the action of nitrous acid on primary nitroalkane?

What is the action of nitrous acid on secondary nitroalkane?

What is the action of nitrous acid on tertiary nitroalkane

What is peptide linkage?

How is tripeptide formed?

Write the reactions involved in the preparation of Teflon

Write the reactions involved in the preparation of Orlon

Write the reactions involved in the preparation of  PVC

What is the position of iron (Z = 26) in periodic table?

Explain why is Fe3+ more stable than Fe2+?

Discuss the mechanism of alkaline hydrolysis of bromomethane.

How is carbolic acid prepared from chlorobenzene?

What is the action of bromine water on carbolic acid?

Write chemical test to distinguish between carbolic acid and alcohol.

Explain cationic complexes and anionic complexes of co-ordination compounds.

Write the structure and IUPAC names of isomeric aldehydes having molecular formula C₅H₁₀O.

Draw the structure of aspirin.