Chemistry 56/1/3 2018-2019 Science (English Medium) Class 12 Question Paper Solution

Arrange the following in decreasing order of solubility in water:
\[\ce{(CH3)3N,(CH3)2NH,CH3NH2}\]

Answer the following question.
What type of stoichiometric defect is shown by ZnS and why?

Answer the following question.
Write one stereochemical difference between S_N1 and S_N2 reactions.

Answer the following question.
Why are medicines more effective in the colloidal state?

Answer the following question.
What is the difference between an emulsion and a gel?

Answer the following question.
What is the basic structural difference between glucose and fructose?

Answer the following question.
Write the products obtained after the hydrolysis of lactose.

Answer the following question.
When MnO₂ is fused with KOH in the presence of KNO₃ as an oxidizing agent, it gives a dark green compound (A). Compound (A) disproportionates in an acidic solution to give a purple compound (B).  An alkaline solution of compound (B) oxidizes KI to compound (C) whereas an acidified solution of compound (B) oxidizes KI to (D). Identify (A), (B), (C), and (D).

State Henry's law.

Write the two applications of Henry's law.

Answer the following question.
Write IUPAC name of the complex [Pt(en)₂CI₂]. Draw structures of geometrical isomers for this complex.

Using IUPAC norms write the formulae for the following:
Hexaamminecobalt(III) sulphate

Using IUPAC norms write the formulae for the following:
Potassium trioxalatochromate (III)

Write a balanced chemical equation for the following process:
XeF₂ undergoes hydrolysis.

Write a balanced chemical equation for the following process:
MnO₂ is heated with conc.HCI

Arrange the following in the order of the property indicated against set :
H₂O, H₂S, H₂Se, H₂Te − increasing acidic character.

Arrange the following in order of the property indicated set.
HF, HCl, HBr, HI - decreasing bond enthalpy.

For a reaction
\[\ce{2H2O2->[I^-][Alkaline medium]2H2O + O2}\]

The Proposed mechanism is given below: 
(1) H₂O₂+I^- → H₂O+IO^-(slow)
(2) H₂O₂+IO^-→H₂O+I^-+O₂(fast)

(i) Write the rate law for the reaction.
(ii) Write the overall order of a reaction.
(iii) Out of steps(1) and (2), which one is the rate-determining step? 

Write the hybridization and magnetic character of the following complexes:
[Fe(H₂O)₆]²⁺
(Atomic no. of Fe = 26)

Write the hybridization and magnetic character of the following complexes:
[Fe(CO)₅]
(Atomic no. of Fe = 26)

Write the structure of main compounds A and B in the following reaction:

\[\ce{CH3CH2CN->[CH3MgBRH/3O+]A->[LiAIH4]B}\]

Write the structure of main compounds A and B in the following reaction:
 

Complete the following reaction:

Complete the following reaction:
\[\ce{(C6H5CH2)2Cd + 2CH3COCI}\]

Complete the following reaction:

\[\begin{array}{cc}
\ce{CH3}\phantom{..............}\\
|\phantom{..............}\phantom{...}\\
\ce{CH3-CH-COOH->[(i) Br2/Red P4][(ii) H2O]}\\
\phantom{.......}\
\end{array}\]

Write a chemical equation for the following reaction: 
Propanone is treated with dilute Ba( OH)₂.

Write chemical equation of the following reaction : 
Acetophenone is treated with `("Zn"("Hg"))/"Conc.HCl"`.

Write chemical equations of the following reaction :
Benzoyl chloride is hydrogenated in the presence of `"Pd"/(BaSO_4)`

What is the role of activated charcoal in gas masks?

A colloidal sol is prepared by the given method in the figure. What is the charge on hydrated ferric oxide colloidal particles formed in the test tube? How is the sol represented?

How does chemisorption vary with temperature?

A 4% solution(w/w) of sucrose (M = 342 g mol⁻¹) in water has a freezing point of 271.15 K. Calculate the freezing point of 5% glucose (M = 180 g mol⁻¹) in water.
(Given: Freezing point of pure water = 273.15 K)

An element crystallizes in fcc lattice with a cell edge of 300 pm. The density of the element is 10.8 g cm⁻³. Calculate the number of atoms in 108 g of the element.

How will you convert the following:
Impure Nickel to pure Nickel

How will you convert the following:
Zinc blende to Zinc metal

How will you convert the following:
[Ag(CN)₂]⁻ to Ag

Give reasons for the following:

The transition metals generally form coloured compounds.

Give reasons for the following:
E⁰ value for (Mn³⁺|Mn²⁺) is highly positive than that for (Cr³⁺|Cr²⁺) couple.

Give reasons for the following:
The chemistry of actinoids elements is not so smooth as that of the lanthanoids.

Why type of drug is used in sleeping pills?

What type of detergent are used in toothpastes?

Why the use of alitame as an artificial sweetener is not recommended?

Define the following term with a suitable example in each:
Broad-spectrum antibiotics

Define the following term with a suitable example in each:
Disinfectants

Define the following term with a suitable example in each:
Cationic detergents

Write the structures of monomers used the following polymers: 
Nylon - 6, 6

Write the structures of monomers used the following polymers:
Glyptal

Write the structures of monomers used the following polymers:
Buna S

Is   a homopolymer or copolymer? Give reason. 

Write the monomers of the following polymer : 

What is the role of Sulphur in the vulcanization of rubber?

Out of (CH₃)₃ C-Br and (CH₃)₃ C-I, which one is more reactive towards S_N1 and why? 

Write the product formed when p-nitro chlorobenzene is heated with aqueous  NaOH at 443K followed by acidification? 

Why dextro and laevo rotatory isomers of Butan-2-ol are difficult to separate by fractional distillation?

Write equations of the following reactions:
Acetylation of aniline

Write equations of the following reactions:
Coupling reaction

Write equations of the following reactions:
Carbyl amine reaction

The decomposition of NH₃ on a platinum surface is a zero-order reaction. If the rate constant (k)  is 4 x 10^-3 ms^-1, how long will it take to reduce the initial concentration of NH₃ from 0.1 M to 0.064 M?

Define the following term:
Oligosaccharides

Define the following term:
Denaturation of protein

Define the following term:
Vitamins

Write the reactions involved when D-glucose is treated with the following reagent:
Br₂ water

Write the reactions involved when D-glucose is treated with the following reagent:
H₂N-OH

Write the reactions involved when D-glucose is treated with the following reagent:
(CH₃CO)₂O

How do you convert the following :
Phenol to anisole

How do you convert the following : 
Ethanol to Propan-2-ol 

Write the mechanism of the following reaction : 

\[\ce{C2H5OH->[H2SO4][443K]CH2=CH2 + H2O}\]

Why phenol undergoes electrophilic substitution more easily than benzene?

Account for the following:
o-nitrophenol is more steam volatile than p-nitrophenol.

Account for the following : 
t-butyl chloride on heating with sodium methoxide gives 2-methylpropene instead of t-butyl methyl ether.

Write the equation involved in the following reaction:

Reimer-Tiemann reaction

Write the reaction involved in the following:
Friedal-Crafts Alkylation of Phenol

Give simple chemical test to distinguish between Ethanol and Phenol.

Give reasons for the following:
Sulphur in vapour state shows paramagnetic behaviour.

Give reasons for the following:
N-N bond is weaker than P-P bond.

Give reasons for the following:
Ozone is thermodynamically less stable than oxygen.

Write the name of gas released when Cu is added to
dilute HNO₃

Write the name of gas released when Cu is added to
conc. HNO₃

Answer the following question.
Write the disproportionation reaction of H₃PO₃. 

Draw the structure of XeF₄. 

Account for the following : 
Although Fluorine has less negative electron gain enthalpy yet F₂ is a strong oxidizing agent.

Account for the following : 
Acidic character decreases from N₂O₃ to Bi₂O₃ in group 15.

Answer the following question.
Write a chemical reaction to test sulphur dioxide gas. write a chemical equation involved.

E°_cell for the given redox reaction is 2.71 V
Mg_(s) + Cu²⁺ _{(0.01 M)} → Mg²⁺ (0.001 M) + Cu_(s)

Calculate E_cell for the reaction. Write the direction of flow of current when an external opposite potential applied is
(i) less than 2.71 V and
(ii) greater than 2.71 V

Solve the following question.
A steady current of 2 amperes was passed through two electrolytic cells X and Y connected in series containing electrolytes FeSO₄ and ZnSO₄ until 2.8 g of Fe deposited at the cathode of cell X. How long did the current flow? Calculate the mass of Zn deposited at the cathode of cell Y.
(Molar mass : Fe = 56 g mol^–1, Zn = 65.3 g mol^–1, 1F = 96500 C mol^–1)

In the plot of molar conductivity (∧_m) vs square root of concentration (c^1/2), following curves are obtained for two electrolytes A and B:

Answer the following:
(i) Predict the nature of electrolytes A and B.
(ii) What happens on extrapolation of ∧_m to concentration approaching zero for electrolytes A and B?