Class 12th Chemistry 2017 Set3 Delhi Board Paper Solution

Give simple chemical tests to distinguish between the following pairs of compounds.

(i) Propanal and Propanone

(ii) Acetophenone and Benzophenone

(iii) Phenol and Benzoic acid

(iv) Benzoic acid and Ethyl benzoate

(v) Pentan-2-one and Pentan-3-one

(vi) Benzaldehyde and Acetophenone

(vii) Ethanal and Propanal

How the following conversions can be carried out?

(i) Propene to propan-1-ol

(ii) Ethanol to but-1-yne

(iii) 1-Bromopropane to 2-bromopropane

(iv) Toluene to benzyl alcohol

(v) Benzene to 4-bromonitrobenzene

(vi) Benzyl alcohol to 2-phenylethanoic acid

(vii) Ethanol to propanenitrile

(viii) Aniline to chlorobenzene

(ix) 2-Chlorobutane to 3, 4-dimethylhexane

(x) 2-Methyl-1-propene to 2-chloro-2-methylpropane

(xi) Ethyl chloride to propanoic acid

(xii) But-1-ene to n-butyliodide

(xiii) 2-Chloropropane to 1-propanol

(xiv) Isopropyl alcohol to iodoform

(xv) Chlorobenzene to p-nitrophenol

(xvi) 2-Bromopropane to 1-bromopropane

(xvii) Chloroethane to butane

(xviii) Benzene to diphenyl

(xix) tert-Butyl bromide to isobutyl bromide

(xx) Aniline to phenylisocyanide

A 5% solution (by mass) of cane sugar in water has freezing point of 271 K. Calculate the freezing point of 5% glucose in water if freezing point of pure water is 273.15 K.

A solution of glucose in water is labelled as 10% w/w, what would be the molality and mole fraction of each component in the solution? If the density of solution is 1.2 g mL^-1, then what shall be the molarity of the solution?

Henry's law constant for CO₂ in water is 1.67 x 10⁸Pa at 298 K. Calculate the quantity of CO₂in 500 mL of soda water when packed under 2.5 atm CO₂ pressure at 298 K.

Calculate the mass of a non-volatile solute (molar mass 40 g mol^-1) which should be dissolved in 114 g octane to reduce its vapour pressure to 80%.

The vapour pressure of pure liquids A and B are 450 and 700 mm Hg respectively, at 350 K. Find out the composition of the liquid mixture if total vapour pressure is 600 mm Hg. Also find the composition of the vapour phase.

Calculate the mole fraction of benzene in solution containing 30% by mass in carbon tetrachloride.

How many mL of 0.1 M HCl are required to react completely with 1 g mixture of Na₂CO₃ and NaHCO₃ containing equimolar amounts of both?

If NaCl is doped with 10^-3mol % of SrCl₂, what is the concentration of cation vacancies?

Explain the difference between Buna-N and Buna-S.

Explain why

(i) the dipole moment of chlorobenzene is lower than that of cyclohexyl chloride?

(ii) alkyl halides, though polar, are immiscible with water?

(iii) Grignard reagents should be prepared under anhydrous conditions?

For the reaction R → P, the concentration of a reactant changes from 0.03 M to 0.02 M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and seconds.

From the rate expression for the following reactions, determine their order of reaction and the dimensions of the rate constants.

(i) 3 NO(g) → N₂O(g)  Rate = k[NO]²

(ii) H₂O₂ (aq) + 3 I ^- (aq) + 2 H⁺→ 2 H₂O (l) +  I₃^-  Rate = k[H₂O₂][I ^- ]

(iii) CH₃CHO(g)  → CH₄(g) + CO(g)  Rate = k [CH₃CHO]^3/2

(iv) C₂H₅Cl(g) → C₂H₄(g) + HCl(g)  Rate = k [C₂H₅Cl]

'Stability of a crystal is reflected in themagnitude of its melting point'. Comment. Collect melting points of solid water, ethyl alcohol, diethyl ether and methane from a data book. What can you say about the intermolecular forces between these molecules?

Name the following halides according to IUPAC system and classify them as alkyl, allyl, benzyl (primary, secondary, tertiary), vinyl or aryl halides:

(i) (CH₃)₂CHCH(Cl)CH₃

(ii) CH₃CH₂CH(CH₃)CH(C₂H₅)Cl

(iii) CH₃CH₂C(CH₃)₂CH₂I

(iv) (CH₃)₃CCH₂CH(Br)C₆H₅

(v) CH₃CH(CH₃)CH(Br)CH₃

(vi) CH₃C(C₂H₅)₂CH₂Br

(vii) CH₃C(Cl)(C₂H₅)CH₂CH₃

(viii) CH₃CH=C(Cl)CH₂CH(CH₃)₂

(ix) CH₃CH=CHC(Br)(CH₃)₂

(x) p-ClC₆H₄CH₂CH(CH₃)₂

(xi) m-ClCH₂C₆H₄CH₂C(CH₃)₃

(xii) o-Br-C₆H₄CH(CH₃)CH₂CH₃

Give reason for the higher boiling point of ethanol in comparison to methoxymethane.

What are the monomeric repeating units of Nylon-6 and Nylon-6, 6?

The HNH angle value is higher than HPH, HAsH and HSbH angles. Why? [Hint: Can be explained on the basis of sp³ hybridisation in NH₃ and only s-p bonding between hydrogen and other elements of the group].

Three electrolytic cells A,B,C containing solutions of ZnSO₄, AgNO₃ and CuSO₄, respectively are connected in series. A steady current of 1.5 amperes was passed through them until 1.45 g of silver deposited at the cathode of cell B. How long did the current flow? What mass of copper and zinc were deposited?