Chemistry (Theory) Set 1 2013-2014 ISC (Commerce) Class 12 Question Paper Solution

Fill in the blanks by choosing the appropriate word/words from those given in the brackets:

(increases, formic acid, decreases, less, zero, small, paired, atoms, unpaired, ions, pentagonal bipyramidal, electrical, more, ethylamine, molecules, propanoic acid, methylamine, chemical)

An electrochemical cell converts ________ energy to _________ energy.

Fill in the blanks by choosing the appropriate word/words from those given in the brackets: 

(increases, formic acid, decreases, less, zero, small, paired, atoms, unpaired, ions, pentagonal bipyramidal, electrical, more, ethylamine, molecules, propanoic acid, methylamine, chemical.)

The crystal of graphite is made-up of ________ while that of sodium chloride is made-up of _______.

Fill in the blanks by choosing the appropriate word/words from those given in the brackets:

(increases, formic acid, decreases, less, zero, small, paired, atoms, unpaired, ions, pentagonal bipyramidal, electrical, more, ethylamine, molecules, propanoic acid, methylamine, chemical.)

Ethyl isocyanide, on hydrolysis with dilute sulphuric acid, gives ______ and _______.

The molar conductance of a solution _______ with dilution, while its specific conductance _______ with dilution.

increases

formic acid

decreases

less

zero

small

paired

atoms

unpaired

ions

pentagonal bipyramidal

electrical

more 

ethylamine

molecules 

propanoic acid

methylamine

chemical

Fill in the blanks by choosing the appropriate word/words from those given in the brackets:

(increases, formic acid, decreases, less, zero, small, paired, atoms, unpaired, ions, pentagonal bipyramidal, electrical, more, ethylamine, molecules, propanoic acid, methylamine, chemical.)

The Van’t Hoff factor of the acetic acid solution is _______ than one and the value of a normal colligative property is ________ than the observed colligative property of this solution.

Of the following terms used for denoting the concentration of a solution, the one which does not get affected by temperature is:

Molarity

Molality

Normality

Formality

Complete the following statement by selecting the correct alternative from the choices given: 

The solubility of calcium hydroxide is s mol litre^-1. The solubility product under the same condition will be: _________.

4s³

2s³

2s²

s³

A current liberates 0.50 g of hydrogen in 2 hours. The weight of copper (at. wt. = 63.5) deposited at the same time by the same current through copper sulphate solution is ______.

63.5 g

31.8 g

15.9 g

15.5 g

Complete the following statement by selecting the correct alternative from the choices given: 

Natural rubber is a : _________

Polyester

Polyamide

Polyisoprene

Polysaccharide

Among the following halogens, the one which does not form an oxyacid is:

Fluorine

Chlorine

Bromine

Iodine

What is the [OH^–] concentration of an acid whose pH is 5 at 25°C?

What happens when a nickel rod is dipped into a copper sulphate solution? Justify your answer.

[\[\ce{E{^{\circ}_{Ni^{+2}/Ni}}}\] = − 0.25 V and \[\ce{E{^{\circ}_{Cu^{+2}/Cu}}}\] = +0.34 V]

Write the equation for the preparation of acetanilide from aniline.

Define Raoult’s law for the elevation of the boiling point of a solution.

An ionic compound is made up of A cations and B anions. If A cations are present at the alternate corners and B anion is present on the body of the diagonal, what is the formula of the ionic compound?

Match the following:

What will be the vapour pressure of a solution containing 5 moles of sucrose (C₁₂H₂₂O₁₁) in 1 kg of water, if the vapour pressure of pure water is 4.57 mm of Hg? [C = 12, H = 1, O = 16]

A 2 molal solution of sodium chloride in water causes an elevation in the boiling point of water by 1.88 K. What is the value of Van’t Hoff factor? What does it signify? [K_b = 0.52 K kg mol⁻¹]

(i)

Write the mathematical expression relating to the variation of the rate constant of a reaction with temperature. 
(ii)

How can you graphically find the activation energy of the reaction from the above expression?
(iii)

The slope of the line in the graph of log k (k = rate constant) versus `1/"T"` is -5841. Calculate the activation energy of the reaction.

Define the Frenkel defect in a solid crystal.

Explain giving reasons, why ionic solids conduct electricity in the molten state, but not in solid-state?

A solution of sodium chloride has no effect on litmus, but a solution of zinc chloride turns blue litmus red.

In a crystal of diamond:

1. How many carbon atoms are present per unit cell?
2. What type of lattice does diamond crystallise in?
3. How many carbon atoms surround each carbon atom?
4. How are they arranged?

What is standard hydrogen electrode?

0.05 M NaOH solution offered resistance of 31.6 ohms in a conductivity cell at 298 K. If the cell constant of the cell is 0.367 cm⁻¹, calculate the molar conductivity of the NaOH solution.

K_c for the reaction is 61.7 at 60°C. What is its unit? Calculate K_p for the reaction and write its unit.

What happens to the equilibrium in a reversible reaction if a catalyst is added to it?

State the effect of the following on the reaction

\[\ce{2SO2_{(g)} + O2_{(g)} ⇌ 2SO3_{(g)} + 189.4}\]kJ at equilibrium:

(i) Temperature is increased.
(ii) The concentration of SO₂ is increased.
(iii) The pressure is decreased.
(iv) Helium is added at constant pressure.

0.3605 g of a metal is deposited on the electrode by passing 1.2 amperes of current for 15 minutes through its salt solution. The atomic weight of the metal is 96. What is the valency of the metal?

Explain why phenolphthalein is used as an indicator of acid-base titration.

Write the formula of the following compound:

Triammine triaquachromium (III) chloride

Write the formula of the following compound:

Potassiumhexacyanoferrate(III)

Name the type of isomerism shown by the following pair of compounds:

[CoCl(H₂O)(NH₃)₄]Cl₂ and [CoCl₂(NH₃)₄]Cl.H₂O

Name the type of isomerism shown by the following pair of compounds:

[Pt(NH₃)₄][PtCl₆] and [Pt(NH₃)₄Cl₂][PtCl₄]

For the complexion of [Co(NH₃)₆]³⁺:

1. State the hybridisation of the complex.
2. State the magnetic nature of the complex.

Write a balanced chemical equation for the following reaction:

Ozone and lead sulphide

Write a balanced chemical equation for the following reaction:

Chlorine is passed through hot concentrated NaOH solution.

Write a balanced chemical equation for the following reaction:

Sulphuric acid is treated with phosphorous.

Give a reason for the following:

Zn²⁺ salts are white but Cu²⁺ salts are blue in colour.

Give a reason for the following:

Fluorine gives only one oxide but chlorine gives a series of oxides.

How is potassium dichromate prepared from a sample of chromite ore? Give balanced equations for the chemical reactions involved.

For the molecule IF₇:

1. Draw the structure of the molecule.
2. State the hybridisation of the central atom.
3. State the geometry of the molecule.

How can the following conversions be brought about:

(i) Acetic acid to methyl cyanide.
(ii) Acetaldehyde to formaldehyde. 
(iii) Nitrobenzene to 2, 4, 6 tribromoaniline.

Identify the reagents A, B, C, D, E and F required for the following conversion:

\[\ce{C6H5NO2->[A]C6H5NH2->[B]C6H5N2+Cl- ->[C]C6H5Cl->[D]C6H5OH->[H2SO4]E + F}\]

The deficiency of which vitamin will cause the following diseases: 
(i) Scurvy
(ii) Haemorrhages

Give one chemical test to distinguish between the following pairs of compounds:

(i) Ethanol and 2 propanols.
(ii) Aniline and ethylamine.

Write the structures of all enantiomers possible for lactic acid.

Give balanced equations for the following reactions: 

(i) Acetaldehyde is heated with hydroiodic acid in the presence of red phosphorous.
(ii) Calcium acetate is subjected to dry distillation.
(iii) Sodium ethoxide is treated with ethyl bromide.
(iv) Benzaldehyde is treated with sodium bisulphite.

An organic compound A with the molecular formula C₇H₈ on oxidation by chromyl chloride in the presence of CCl₄ gives a compound B which gives positive tollen’s test. The compound B on treatment with NaOH followed by acid hydrolysis gives two products C and D. C on oxidation gives B which on further oxidation gives D. The compound D on distillation with soda-lime gives a hydrocarbon E. Below 60°C, concentrated nitric acid reacts with E in the presence of concentrated sulphuric acid forming a compound F. Identify the compounds A, B, C, D, E, and F.

Give a balanced equation for the following name reaction:

Clemmensen’s reduction.

Give a balanced equation for the following name reaction: 

Kolbe’s electrolytic reaction.

Give a balanced equation for the following name reaction:

 Balz-Schiemann’s reaction

What do you observe when glucose is treated with bromine water?

What is the isoelectric point?

Answer the following: 
(i) What is biuret test?
(ii) Write a balanced equation for the formation of biuret.