Mock Test-1 (Paper-1) (Question 51-100)

Total Questions: 50

31. Which one of the following is not a chemical change?

Correct Answer: (c) Freezing of water
Solution:Freezing of water is not a chemical change as ice when melt changes back to water showing physical change.

32. Which one of the following acids is used for etching glass?

Correct Answer: (c) HF
Solution:Hydrofluoric acid (HF) is used in the etching of glass.

33. Consider the following statements : The purpose of adding sodium sulphate and sodium silicate to washing power is —

1. To keep washing powder dry

2. to maintain the alkalinity of the power

which of these statements is/are correct?

Correct Answer: (c) Both 1 and 2
Solution:The addition of silicates to synthetic detergents has proved very beneficial. Silicates soften water by the formation of precipitates that can be easily rinsed away. Soluble silicates contribute to detergents as cleaning aids, processing aids, and corrosion inhibitors. As cleaning aids, and corrosion inhibitors.

As cleaning aids, soluble silicates provide alkalinity and promote soil suspension. Sodium Sulphate is simply a filler in detergent powder, in much the same way as fillers are used in many medical tablets, it doesn't play any active role as such.

34. To study meiosis in plants, the best part would be —

Correct Answer: (c) anthers
Solution:In plants, meiosis occurs in the reproductive cells like in anthers and Ovary. In anthers pollen grains are formed by meiosis and within the ovary to form ovules.

35. The main constituents of biogas are

Correct Answer: (a) Methane and Carbon di-oxide
Solution:Biogas comprises primarily methane (CH₄) and carbon dioxide (CO₂) and may have small amount of hydrogen sulphide (H₂S), moisture and siloxanes.

36. When hot water is placed into an empty water bottle, the bottle keeps its shape and does not soften. What type of plastic is the water bottle made from?

Correct Answer: (d) Thermosetting
Solution:Thermoset, or thermosetting, plastics are synthetic materials that strengthen during being heated, but cannot be successfully remolded or reheated after their initial heat-forming. This is in contrast to thermoplastics, which soften when heated and harden and strengthen after cooling.

37. Among the following fuels of energy, which is the most environment friendly?

Correct Answer: (c) CNG
Solution:Since CNG is based primarily on methane, it can be combusted without releasing too much carbon into the atmosphere. This makes CNG a much more environmentally friendly fuel alternative to petroleum and gasoline.

38. A body is charged negatively. It implies that

Correct Answer: (b) it has acquired some electrons from outside
Solution:Atoms are neutral. When an atom loses electron, it becomes negatively charged. Hence, a body is charged negatively when it has acquired some electrons from outside.

39. The kingdom Protista is primarily made up of organisms that are

Correct Answer: (d) eukaryotic and single-celled
Solution:All single - called eukaryotes are placed under Protista. This kingdom forms a link with others dealing with plants, animals and fungi.

40. The camel's hump is composed of a tissue. It is a type of

Correct Answer: (c) adipose tissue
Solution:The camel's hump is composed of adipose tissue.