DIRECTION : These are Assertion-Reason type question.Question contains two statements:Statement-1 (Assertion) and Statement-2 (Reason). Answer these questions from the following four options.

Statement-1 :Calgon is used for removing permanent hardness of water.
Statement-2 :Calgon forms precipitates with Ca²⁺ and Mg²⁺.

Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement -1
Statement-1 is True, Statement -2 is True ; Statement-2 is NOT a correct explanation for Statement - 1
Statement-1 is True, Statement- 2 is False
Statement-1 is False, Statement -2 is True

Solution

Both assertion (A) is correct reason (R) is not true.Correct Reason : Calgon forms soluble complexes with Ca²⁺ and Mg²⁺ in which properties of these ions are masked.

DIRECTION : These are Assertion-Reason type question.Question contains two statements:Statement-1 (Assertion) and Statement-2 (Reason). Answer these questions from the following four options.

Statement-1 :Hydrogen combines with other elements by losing, gaining or sharing of electrons.
Statement-2 : Hydrogen forms electrovalent and covalent bonds with other elements

Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement -1
Statement-1 is True, Statement -2 is True ; Statement-2 is NOT a correct explanation for Statement - 1
Statement-1 is True, Statement- 2 is False
Statement-1 is False, Statement -2 is True

DIRECTION : These are Assertion-Reason type question.Question contains two statements:Statement-1 (Assertion) and Statement-2 (Reason). Answer these questions from the following four options.

Statement-1 : H₂O₂ is not stored in glass bottles.
Statement-2 :Alkali oxides present in glass catalyse the decomposition of H₂O₂

Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement -1
Statement-1 is True, Statement -2 is True ; Statement-2 is NOT a correct explanation for Statement - 1
Statement-1 is True, Statement- 2 is False
Statement-1 is False, Statement -2 is True

DIRECTION : These are Assertion-Reason type question.Question contains two statements:Statement-1 (Assertion) and Statement-2 (Reason). Answer these questions from the following four options.

Statement-1 :Temporary hardness can be removed by boiling.
Statement-2 :On boiling the soluble bicarbonates change to carbonates which being insoluble, get precipitated.

Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement -1
Statement-1 is True, Statement -2 is True ; Statement-2 is NOT a correct explanation for Statement - 1
Statement-1 is True, Statement- 2 is False
Statement-1 is False, Statement -2 is True

DIRECTION : These are Assertion-Reason type question.Question contains two statements:Statement-1 (Assertion) and Statement-2 (Reason). Answer these questions from the following four options.

Statement-1 :Decomposition of H₂O₂ is a disproportionation reaction
Statement-2 : H₂O₂ molecule simultaneously undergoes oxidation and reduction.

Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement -1
Statement-1 is True, Statement -2 is True ; Statement-2 is NOT a correct explanation for Statement - 1
Statement-1 is True, Statement- 2 is False
Statement-1 is False, Statement -2 is True

Solution

Both statement-1 and statement-2 are true and statement-2 is the correct explanation of statement-1.

Which of the following gas is insoluble in water ?

SO₂
NH₃
H₂
CO₂

Solution

Hydrogen is the lightest gas. It is insoluble in water.

Hydrogen can be fused to form helium at

High temperature and high pressure
High temperature and low pressure
Low temperature and high pressure
Low temperature and low pressure

Solution

A fusion reaction is difficult to occur because positively charged nuclei repel each other. At very high temperature of the order of 106 to 107K, the nuclei may have sufficient energy to overcome the repulsive forces and fuse. It is for this reason, fusion reactions are also called thermonuclear reactions. Hence, hydrogen can be fused to form helium at high temperature and high pressure.

Which of the following reaction produces hydrogen

Mg + H₂O
BaO₂ + HCl
H₂S₄O₈+ H₂O
Na₂O₂ + 2HCl

Solution

Mg + 2H₂O ⟶ Mg(OH)₂ + H₂↑

Some statements about heavy water are given below:
(A)Heavy water is used as a moderator in nuclear reactors.
(B)Heavy water is more associated than ordinary water.
(C)Heavy water is more effective solvent than ordinary water.
Which of the above statements are correct?

(A) and (C)
(A) and (B)
(A), (B) and (C)
(B) and(C)

When H₂O₂ is oxidised the product is

OH^-
O₂
O^2-
\(HO_{2}^{-}\)

Solution

UnAttempted

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