56: Assertion (A) :
Synthetic detergents can lather well in hard water.
Reason (R) :
Synthetic detergents form soluble calcium and magnesium salts with hard water.
(a) Both A and R are individually true and R is the correct explanation of A
(b) Both A and R are individually true but R is not a correct explanation of A
(c) A is true but R is false
(d) A is false but R is true
Explanation:
Synthetic detergents can lather well in hard water because they form soluble and magnesium salts with hard water.
57: Soft drinks such as colas contain significant quantities of
(a) caffeine
(b) nicotine
(c) tannin
(d) renin
58: Which one of the following approaches comes under the category of biotechnology?
(a) Use of living organisms or substances obtained from them in industrial processes
(b) Modernizing the commercial industries to produce products for use in biological research
(c) Use of modern technology to investigate biological disorders
(d) Use of industrial technology to increase the biosphere
59: A married couple adopted a male child. A few years later twin boys were born to them. The blood group of the couple is 'AB' positive and 'O' negative. The blood group of the three sons is A positive, B positive, and 'O' positive. The blood group of the adopted son is
(a) A positive
(b) B positive
(c) O positive
(d) Cannot be determined
Explanation:
Couple with AB positive blood group consist of A+ and B+ gene and with O negative blood group consist of O- gene. A+ gene is dominant over O gene which results into A+ blood group in one child. B+ gene is dominant over O- gene which results into B+ blood group in other child.
So the blood group of the adopted son would be O positive.
60: Aluminium surfaces are often anodized. This means the deposition of a layer of
(a) chromium oxide
(b) aluminium oxide
(c) nickel oxide
(d) zinc oxide
Explanation:
Due to less positive charge of zinc, aluminium rod attracts zinc from zinc solution and hence zinc is oxide is deposited as a layer.