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

Out of NaCl and AgCl, which one shows Frenkel defect and why? 

Arrange the following in increasing order of boiling points:

(CH₃)₃ N, C₂ H₅ OH, C₂ H₅ NH₂

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?

What are ambident nucleophiles? Explain with an example.

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.

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

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.

State Raoult’s law for a solution containing volatile components. Write two characteristics of the solution which obey Raoult’s law at all concentrations. 

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? 

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).

Write IUPAC name of the complex [Pt(en)2Cl2]. Draw structures of geometrical isomers for this complex. 

Using IUPAC norms write the formula of Hexaamminecobalt (III) sulphate. 

Using IUPAC norms write the formulae of  Potassium trioxalatochromate (III) 

Out of [CoF₆]^3- and [Co(en)₃]³⁺, which one complex is
(i) paramagnetic
(ii) more stable
(iii) inner orbital complex and
(iv) high spin complex
(Atomic no. of Co = 27) 

Write structures of compounds A and B of the following reaction : 

Write structures of compounds A and B of the following 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?

What is the role of activated charcoal in a gas mask? 

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 solution represented? 

How does chemisorption vary with temperature?

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.

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) 

Name the method of refining which is Used to obtain semiconductor of high purity. 

Name the method of refining which is Used to obtain low boiling metal.

Write chemical reactions taking place in the extraction of copper from Cu₂ S. 

How would you account for the following? 

Transition metals and their compounds act as catalysts.

Give a reason for the following: 

 E° value for (Mn²⁺|Mn) is negative whereas for  (Cu²⁺|Cu) is positive. 

Give a reason for the following: 

Actinoids show irregularities in their electronic configurations.

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 vulcanisation of rubber?

What use of drugs is used in sleeping pills?

What type of detergents are used in toothpaste? 

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

Define Broad-spectrum antibiotics with a suitable example?

Define disinfectants with a Suitable example?

Define the following term with a suitable example: 
Cationic detergents

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 laevorotatory isomers of Butan-2-ol are difficult to separate by fractional distillation? 

An aromatic compound 'A' on heating with Br₂ and KOH forms a compound 'B' of molecular formula C₆H₇N which on reacting with CHCl₃ and alcoholic KOH produces a foul-smelling compound 'C'. Write the structures and IUPAC names of compounds A, B, and C.

complete the following reaction: 

complete the following reaction:

\[\ce{(C6H5CH2)2Cd + 2CH3COCl}\]

complete the following reaction: 

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

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)`

Differentiable between the following: 
Amylose and Amylopectin 

Differentiate between the following :

Peptide linkage and Glycosidic linkage 

Differentiate between  the following :

 Fibrous proteins and Globular proteins 

Write a chemical reaction to show that the open structure of D-glucose contains the following : 

 Straight chain 

Write a chemical reaction to show that the open structure of D-glucose contains the following :  

Five alcohol groups

Write a chemical reaction to show that the open structure of D-glucose contains the following : 

 Aldehyde as a carbonyl group 

E°cell for the given redox reaction is 2.71V
\[\ce{Mg_{(s)} +Cu^{2+}_{(0.01 M)}->Mg^{2+}_{(0.001M)}+Cu_{(s)}}\]
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 

A steady current of 2 amperes was passed through two electrolytic cells X and Y connected in series containing electrolytes FeSO₄and ZnSO₄ until 2.8g 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=56g mol^-1,Zn=65.3g mol^-1,1F=96500C 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 the extrapolation of ∧_m to concentration approaching for electrolytes A and B?

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 equation involved in Friedal-Crafts Alkylation of Phenol 

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

Ethanol and phenol

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

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

Give a reason 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 the 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.