Question1.

Which of the following is used to make semiconductor devices and transistors?

(a) Ultrapure form of germanium

(b) Ultrapure form of silicon

(c) Both (a) and (b)

(d) Neither (a) nor (b)

 

Question2.

SiCl₆^2- does not exist but SiF₆^2- exists. Explain.

 

Question3.

Assertion: Metal borides are used as protective shields and control rods in nuclear industry.

Reason: The boron-10 (¹⁰B) isotope has high ability to absorb neutrons.

(a) Both A and R are true and R is the correct explanation of A.

(b) Both A and R are true, but R is not the correct explanation of A.

(c) A is true, but R is false.

(d) A is false, but R is true.

 

Question4.

An allotrope of carbon C₆₀ contains

(a) 16 hexagons and 16 pentagons

(b) 20 hexagons and 12 pentagons

(c) 12 hexagons and 20 pentagons

(d) 18 hexagons and 14 pentagons

 

Question5.

Correct order of tendency of catenation in group 14 elements is

(a) C > Si > Ge > Sn

(b) C >> Si > Ge ≈ Sn

(c) Si > C > Sn > Ge

(d) Ge > Sn > Si > C

 

Question6.

B forms only [BF₄]^- which one of the following is formed by Al?

1) [AlF₄]^-

2) [AlF₆]^3-

3) [AlF₄]^3-

4) [AlF₆]^-

 

Question7.

The element which can be used for measuring high temperature and exists in liquid state for a wide range of temperature is

(a) B

(b) Al

(c) Ga

(d) In

 

Question8.

Assertion: Sulphur forms many compounds in which the octet rule is obeyed.

Reason: Due to the absence of d-orbitals in sulphur, it follows the octet rule.

(a) Both A and R are true and R is the correct explanation of A.

(b) Both A and R are true, but R is not the correct explanation of A.

(c) A is true, but R is false.

(d) A is false, but R is true.

 

Question9.

What happens when Boron trichloride reacts with Hydrogen at high temperature?

 

Question10.

(i) Select the member of group 13 that

(a) shows diagonal relation with silicon

(b) is commonly found in +1 oxidation state.

(ii) Select the member(s) of group 14 that

(a) forms the most acidic dioxide.

(b) is commonly found in +2 oxidation state.  

 

Question11.

Why Anhydrous AlCl₃ is more soluble in diethyl ether?

 

Question12.

Although Al is above Hydrogen in the electrochemical series, it is stable in air and water. Why?

 

Question13.

Identify (A) to (F) and give chemical reactions for the reactions at steps (i) to (iv).

(i) A white precipitate (B) is formed when a mineral (A) is boiled with Na₂CO₃ solution.

(ii) The precipitate is filtered and the filtrate contains two compounds (C) & (D). The compound (C) is removed by crystallisation and when CO₂ is passed through the mother liquor left, (D) changes to (C).

(iii) The compound (C) on strong heating gives two compounds (D) and (E).

(iv) (E) on heating with cobalt oxide produces blue coloured substance (F).

 

Question14.

What is Inorganic benzene? Why it is so called? How will you get it from diborane?

 

Question15.

First ionisation enthalpy for the elements of group 13 follows the order

(a) B > Al > Ga > In > Tl

(b) B < Al < Ga < In < Tl

(c) B < Al > Ga < In > Tl

(d) B > Al < Ga > In < Tl

 

Question16.

Solid CO₂ is known as dry ice. Why?

 

Question17.

Write the balanced equation for reaction of Al₄C₃ & CaNCN with water.

 

Question18.

Which silicon compound is used as:

1) Thermal Insulator

2) Lubricant

3) Cation exchanger

 

Question19.

What happens when Red lead is treated with Nitric acid?

 

Question20.

Starting from SiCl₄ prepare Na₂SiO₃ in three steps (give reactions only).

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