Chemistry 2013-2014 HSC Science (General) 12th Standard Board Exam Question Paper Solution

Define boiling point

Define cell constant.

Derive a relation between ΔH and ΔU for a chemical reaction. Draw neat labelled diagram of calomel electrode. Resistance and conductivity of a cell containing 0.001 M KCI solution at 298K are 1500Ω and 1.46x10^-4 S.cm^-1 respectively.

Write molecularity of the following reaction:

2NO_(g)+O_2(g)→2NO_2(g)

What is calcination?

How does calcination differ from roasting?

Write resonating structures of ozone.

The decomposition of N₂O_5(g) at 320K according to the following equation follows first order reaction:

`N_2O_(5(g))->2NO_(2(g))+1/2O_(2(g))`

The initial concentration of N₂O_5(g) is 1.24 x 10^-2 mol. L-1 and after 60 minutes 0.20x10^-2 molL^-1. Calculate the rate constant of the reaction at 320K.

One mole of a gas expands by 3L against a constant pressure of 3 atmosphere. Calculate the work done in -

(a) L.atmosphere

(b) Joules

(c) Calories

Calculate the amount of CaCl₂ (van't Hoff factor i = 2.47) dissolved in 2.5 L solution so that its osmotic pressure at 300K is 0.75 atmosphere.

Given : Molar mass of CaCl₂ is 111g mol^-1

R=0.082 L.atm K^-1mol^-1

Describe anomalous behaviour of fluorine with the other elements of group 17 wilh reference to :

(a) Hydrogen bonding

(b) Oxidation state

(c) Polyhalide ions

Face centred cubic crystal lattice of copper has density of 8.966 g.cm^-3. Calculate the volume of the unit cell. Given molar mass of copper is 63.5 g mol^-1 and Avogadro number N_A is 6.022 x 10²³ mol^-1

What is the action of the following reagents on ammonia : 
Nessler's reagent

What is the action of the following reagents on ammonia :
Sodium metal

State the first law of electrolysis

State second law of electrolysis

Draw neat and labelled diagram of Bessermer converter used in the extraction of copper.

Derive the relation between half life and rate constant for a first order reaction

Derive the relation between `DeltaG^@`and equilibrium constant (K) for the reaction -

aA_bB ⇌ cC+dD.​

Explain brown ring test with the help of chemical equation

Explain, why do aquatic animals prefer to stay at lower level of water during summer?

Distinguish between crystalline solid and amorphous solid

To prepare n-type semiconductor the impurity to be added to silicon should have the following number of valence electrons:

(a) 2

(b) 3

(c) 4

(d) 5

Number of faradays of electricity required to liberate 12 g of hydrogen is:

1

8

12

16

What is molecular formula of oleum?

(a) H₂SO₃

(b) H₂SO₄

(c) H₂S₂O₇

(d) H₂S₂O₈

Purification of aluminium by electrolytic refining is carried out by

(a)Hoope process

(b)Hall process

(c)Baeyer process

(d)Serperck process

The rate of reaction for certain reaction is expressed as:

`1/3(d[A])/dt=-1/2(d[B])/dt=-(d[C])/dt`

 The reaction is ______.

3A → 2B + C

2B → 3A + C

2B + C → 3A

3A + 2B → C

A system absorbs 640 J heat and does work of 260 J, the change in internal energy of the system will be

(a) +380J

(b) -380J

(c) +900J

(d) -900J

Which of the following is not a colligative property?

Vapour pressure

Depression in freezing point

Elevation in boiling point

Osmotic pressure

Write the structural formula and IUPAC names of all possible isomers of the compound with molecular formula C₃H₈O.

Write 'two' uses of phenol.

What happens when glucose is treated with Bromine water

What happens when glucose is treated with - Dilute nitric acid

What happens when glucose is treated with Hydrogen cyanite (HCN).

Write the molecular formula and structural formula of BHA and BHT.

Write a note on aldol condensation.

What are thermoplastic polymers?

What is the action of the following reagents on aniline?

Bromine water

What is the action of the following reagents on aniline?

Acetic anhydride

What is the action of the following reagents on aniline?

Hot and conc. sulphuric acid

Discuss the optical activity of lactic acid.

Write balanced chemical equations for action of potassium permanganate on: Hydrogen

Write balanced chemical equations for action of potassium permanganate on Warm conc. sulphuric acid

Explain why Mn²⁺ ion is more stable than Mn³⁺? (Given : Mn→ Z=25)

What is ‘effective atomic number’ (EAN)?

Calculate EAN of cobalt (Z=27) in [CO(NH₃)₆]⁺³ and of zinc (Z=30) in [Zn(NH₃)₄]SO₄.

What is a soap ?

How soap is prepared?

Identify the compounds 'A' and 'B' in the following equation:

Write a note on the self oxidation-reduction reaction of an aldehyde with a suitable example.

Write names and chemical formulae of monomers used in preparing Buna-S.

Define complex lipids

Mention 'two' functions of lipids

Distinguish between S_N1 and S_N2 mechanism of substitution reaction.

What are lanthanoids?

What is the position of actinoids in periodic table ?

How is Methoxyethane prepared from : Methyl iodide

How is Methoxyethane prepared from : Diazomethane

IUPAC name of K₄[Fe(CN)₆] is

 tetrapotassium ferrocyanide

potassium ferricyanide

potassium ferrocyanide

potassium hexacyanoferrate

Carbon atom in methyl carbocation contains how many pairs of electrons?

(a) 8

(b) 4

(c) 3

(d) 5

How many moles of acetic anhydride will be required to form glucose pentaacetate from 2M of glucose?

(a) 2

(b) 5

(c) 10

(d) 2.5

Identify the weakest base amongst the following :

(a) p- methoxyaniline

(b) o-toluidine

(c) benzene - 1, 4 - diamine

(d) 4 - aminobenzoic acid

Bakelite is the polymer of:

(a) Benzaldchyde and phenol

(b) Acetaldehyde and phenol

(c) Formaldehyde and phenol

(d) Formaldehyde and benzyl alcohol

Formalin is 40% aqueous solution of:

(a) Methanal

(b) Methanoic acid

(c) Methanol

(d) Methanamine

Which among the following pairs of elements is 'not' an example of chemical twins?

Zr and Hf

Nb and Ta

Mo and W

Ta and Re