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Assertion (A) : Alloys are commonly used in electrical heating devices like electric iron and heater. Reason (R) : Resistivity of an alloy is generally higher than that of its constituent metals but the alloys have low melting points then their constituent metals. (a) Both (A) and (R) are true and (R) is correct explanation of the assertion. (b) Both (A) and (R) are true but (R) is not the correct explanation of the assertion. (c) (A) is true but (R) is false. (d) (A) is false but (R) is true.

(A) is true but (R) is false. Explanation Alloys always show high resistivity than pure original metal but have relatively... View Article

Assertion (A) : Following are the members of a homologous series : CH3OH, CH3CH2OH, CH3CH2CH2OH Reason (R) : A series of compounds with same functional group but differing by – CH2 – unit is called a homologous series. (a) Both (A) and (R) are true and (R) is correct explanation of the assertion. (b) Both (A) and (R) are true but (R) is not the correct explanation of the assertion. (c) (A) is true but (R) is false. (d) (A) is false but (R) is true.

a) Both (A) and (R) are true and (R) is correct explanation of the assertion. Explanation Homologous series is a series... View Article

An aqueous solution ‘A’ turns phenolphthalein solution pink. On addition of an aqueous solution ‘B’ to ‘A’, the pink colour disappears. The following statement is true for solution ‘A’ and ‘B’. (a) A is strongly basic and B is a weak base. (b) A is strongly acidic and B is a weak acid. (c) A has pH greater than 7 and B has pH less than 7. (d) A has pH less than 7 and B has pH greater than 7.

(c) A has pH greater than 7 and B has pH less than 7. Explanation Phenolphthalein solution turns pink in... View Article

Several factories were pouring their wastes in rivers A and B. Water samples were collected from these two rivers. It was observed that sample collected from river A was acidic while that of river B was basic. The factories located near A and B are (a) Soaps and detergents factories near A and alcohol distillery near B. (b) Soaps and detergents factories near B and alcohol distillery near A. (c) Lead storage battery manufacturing factories near A and soaps and detergents factories near B. (d) Lead storage battery manufacturing factories near B and soaps and detergents factories near A.

(b) Soaps and detergents factories near B and alcohol distillery near A. Explanation Waste of alcohol distillery has pH of... View Article

A diagram of traditional water harvesting system is given below : The statement which defines the system and its parts is (a) This is an ideal setting of the Khadin system and A = Catchment area; B = Saline area & C = Shallow dugwell (b) This is an ideal setting of the Shallow dugwell system and A = Catchment area; B = Saline area and C = Khadin (c) This is an ideal setting of Catchement area and A = Khadin, B = Saline area and C = Shallow dugwell (d) This is showing Saline area and A = Catchment area; B = Khadin and C = Shallow dugwell

(a) This is an ideal setting of the Khadin system and A = Catchment area B = Saline area C =... View Article