Chemistry (Theory) Set 1 2018-2019 ISC (Commerce) Class 12 Question Paper Solution

 Fill in the blanks by choosing the appropriate word/words from those given in the brackets: 
(more than, primary, cathode, Lucas reagent, two, four, less than, Grignard’s reagent, tertiary anode, zero, equal to, three)
 The elevation of boiling point of 0.5 M K2SO4 solution is ________ that of 0.5 M urea solution. The elevation of boiling point of 0.5 M KCl solution is _______ that of 0·5 M K2SO4 solution. 

 Fill in the blanks by choosing the appropriate word/words from those given in the brackets: 
(more than, primary, cathode, Lucas reagent, two, four, less than, Grignard’s reagent, tertiary anode, zero, equal to, three)
A mixture of conc. HCl and anhydrous ZnCl2 is called _______ which shows maximum reactivity with _________ alcohol. 

 Fill in the blanks by choosing the appropriate word/words from those given in the brackets: 
 In electrolytic refining the impure metal is made ________ while a thin sheet of pure metal is used as ___________.

Fill in the blanks by choosing the appropriate word/words from those given in the brackets: 
When the concentration of  reactant of first order reaction  is doubled, the rate of reaction becomes ________ times, but for a ________ order reaction, the rate of reaction remains the same. 

Select the correct alternative from the choices given :
 The cell reaction is spontaneous or feasible when emf of the cell is:

negative

positive

zero

either positive or negative 

 Select the correct alternative from the choices given :
 Which, among the following polymers, is a polyester: 

 melamine 

bakelite

 terylene 

polythene

Select the correct alternative from the choices given :
The correct order of increasing acidic strength of the oxoacids of chlorine is: 

  HClO₃ < HClO₄ < HClO₂ < HClO 

HClO < HClO₂ < HClO₃ < HClO₄ 

HClO₂ < HClO < HClO₄ < HClO₃ 

HClO₃ < HClO₄ < HClO < HClO₂ 

Select the correct alternative from the choices given :
 A catalyst is a substance which: 

changes the equilibrium constant of the reaction 

 increases the equilibrium constant of the reaction 

supplies energy to the reaction 

shortens the time reach equilibrium 

 Match the following: 
(i) Diazotisation             (a) Anisotropic
(ii) Crystalline solid       (b) Reimer-Tiemann reaction
(iii) Phenol                     (c) Diphenyl

Answer the followiiig questions: 
Which trivalent ion has maximum size in the Lanthanoid series i.e. Lanthanum ion (La³⁺) to Luteium ion (Lu³⁺)? 
(at. no. of Lanthanum  = 57 and Lutetium = 71) 

 Answer the followiiig questions: 
When coordination compound  3 3 .6 CoCl NH is mixed with 3, AgNO three moles of AgCl are precipitated per mole of the compound. Write the stuctural formula and IUPAC name of the coordination compound. 
[ Co ( NH₃)₆ ]  Cl₃
Hexamine cobalt (III) chloride

Answer the followiiig questions: 
Calculate the boiling point of urea solution when 6 g of urea is dissolved in 200 g of water.
(Kb for water = 0.52 K kg mol–1, bolining point of pure water = 373 K, mol. wt. of urea = 60) 

Answer the followiiig questions: 
Identify the compounds A, B, C and D in the given reaction:

 For a reaction , A + B → C+D  the initial rate for different reactions and initial concentrations of reactants are given below:

(i) What is the overall order of reaction?
(ii) Write the rate law equation.

25% of first order reaction is completed in 30 minutes. Calculate the time taken in minutes for the reaction to go to 90% completion. 

Name the type of drug which lowers the body temperature in high fever condition.

What are tranquilizers? Give one example of tranquilizer.

Write the balanced chemical equation of the following:

Chlorobenzene treated with ammonia in the presence of Cu₂O at 475 K and 60 atm.

Write the balanced chemical equation of the following:

Ethyl chloride treated with alcoholic potassium hydroxide.

Name the monomer and the type of polymerisation that takes place when PTFE is formed.

Name the monomers of nylon 6, 6.

Name two water-soluble vitamins and the diseases caused by their deficiency in the diet of an individual.

How will you obtain the following? (Give balanced chemical equation):

Benzene from phenol. 

How will you obtain the following? (Give balanced chemical equation):

Iodoform from ethanol 

Give a balanced equation for the preparation of salicylaldehyde from phenol.

How will you obtain the following? (Give balanced chemical equation): Propan-2-ol from Grignard’s reagent.

Show that for a first-order reaction the time required to complete 75% of reaction is about 2 times more than that required to complete 50% of the reaction.

When 0.4g of oxalic acid is dissolved in 40g of benzene, the freezing point of the solution is lowered by 0.45 K. Calculate the degree of association of acetic acid. Acetic acid forms dimer when dissolved in benzene.
(K_f for benzene = 5.12 K kg mol^-1, at. wt. C = 12, H = 1, O = 16)

A solution is prepared by dissolving 9.25 g of non-volatile solute in 450 mL of water. It has an osmotic pressure of 350 mm of Hg at 27°C. Assuming the solute is non-electrolyte, determine its molecular mass. (R = 0.0821 lit atm K^-1 mol^-1)

An element occurs in a body-centred cubic structure. Its density is 8.0 g/cm³. If the cell edge is 250 pm, calculate the atomic mass of an atom of this element. (N₀ = 6.023 × 1023)

Describe the role of the Cryolite in the extraction of aluminium from pure alumina.

Describe the role of the NaCN in the extraction of silver from silver ore.

What is the role of coke in the extraction of iron from its oxides?

Write the IUPAC name of the K₃[Fe(C₂O₄)₃].

Write the IUPAC names of the Co(NH3)5ClSO4

[Fe(CN)₆]⁴- is a coordination complex ion.
Calculate the oxidation number of iron in the complex.

[Fe(CN)₆]⁴- is a coordination complex ion.

Is the complex ion diamagnetic or paramagnetic?

[Fe(CN)₆]^4- is a coordination complex ion.
What is the hybridisation state of the central metal atom? 

[Fe(CN)₆]^4- is a coordination complex ion.

Write the IUPAC name of the complex ion. 

Explain why transition elements form alloys.

Explain why Zn²⁺ salts are white whereas Cu²⁺ salts are coloured.

Explain why transition metals and their compounds act as a catalyst.

Complete and balance the chemical equations:

KMnO₄ + H2SO₄ + H2C2O₄ → ____ + ____ + ____ + _____ 

Complete and balance the chemical equation:

\[\ce{K2Cr2O7 + H2SO4 + KI →}\] _____ + _____ + _____ + _____.

Complete and balance the chemical equations:

K₂Cr₂O₇ + H₂SO₄ + FeSO₄ → _____ + _____ + _____ + _____ 

Give balanced equation for the following:

Aniline is treated with bromine water. 

Give balanced equation for the following:

Ethylamine is heated with chloroform and alcoholic solution of potassium hydroxide.

Give balanced equation for the following:

Benzene diazonium chloride is treated with an ice-cold solution of aniline in acidic medium. 

Define the following term with suitable examples:

Peptisation

Define the following term with suitable examples:

Electrophoresis.

Define the following term with suitable examples:

Dialysis 

Calculate the mass of silver deposited at cathode when a current of 2 amperes is passed through a solution of AgNO₃ for 15 minutes.
(at. wt. of Ag= 108, 1F = 96500 C)

Calculate the emf and ΔG for the cell reaction at 298 K
Mg(s)|Mg²⁺(0.1 M) || CU²⁺(0.01 M)|Cu(s)
Given E°cell = 2.71 V
1F = 96,500 C

Define the following term Specific conductance.

Define the following term Kohlrausch’s Law.

Explain why:

(1) Fluorine has a lower electron affinity than chlorine.
(2) Red phosphorus is less reactive than white phosphorus.
(3) Ozone acts as a powerful oxidising agent.

Draw the structures of the following :
(1) XeF₆
(2) IF₇

Explain why:

(1) Interhalogen compounds are more reactive than the related elemental halogens.
(2) Sulphur exhibits the tendency for catenation but oxygen does not.
(3) On being slowly passed through water, PH₃ forms bubbles but NH₃ dissolves.

Complete and balance the following reactions:

(1) P₄ + H₂SO₄ → ____ + _____ + _____ + _____
(2) Ag + HNO₃(dilute) → _____ + ______ + _____ + _____

Give balanced chemical equations for the following reactions:

(1) Acetaldehyde reacts with hydrogen cyanide.
(2) Acetone reacts with phenylhydrazine.
(3) Acetic acid is treated with ethanol and a drop of conc. H₂SO₄.

Give one chemical test each to distinguish between the following pairs of compounds:
(1) Acetone and benzaldehyde.
(2) Phenol and benzoic acid.

Write a chemical equation to illustrate the following name reaction:

Aldol condensation.

Write a chemical equation to illustrate the following name reaction:

Cannizzaro’s reaction.

Write a chemical equation to illustrate the following name reaction:

Benzoin condensation

Identify the compounds A and B in the given reactions:

(1) 

(2)

\[\ce{CH3COCH3 ->[{[O]}][HNO3(conc.)]A->[PCl5]B}\]