Chemistry Quiz For SSC CGL Exam 2019-20 : 14th December

Q1. Solder used in soldering metal pieces consists of any alloy of:
(a) Tin and Zinc
(b) Tin and Lead
(c) Tin, Zinc and Copper
(d) Tin, Lead and Zinc

Q2. Which one of the following is used in the manufacture of soaps?
(a) Vegetable oil
(b) Mobil oil
(c) Kerosene oil
(d) Cutting oil

Q3. Milk openly placed for sometime becomes sour due to-
(a) Carbonic acid
(b) Lactic acid
(c) Citric acid
(d) Acetic acid

Q4. Which one of the following substances is used in the preservation of food stuff?
(a) Citric Acid
(b) Potassium Chloride
(c) Sodium Benzoate
(d) Sodium Chloride

Q5. ‘Humus’ is an example of-
(a) Soil structure
(b) Crystalloids
(c) Organic colloids
(d) None of the above

Q6. Which of the following chemicals is used in foam fire extinguishers?
(a) Aluminium sulphate
(b)Copper sulphate
(c) Cobalt sulphate
(d) Nickel sulphate

Q7. The predominant organic acid in grapes is-
(a) Formic acid
(b) Benzoic acid
(c) Lactic acid
(d) Tartaric acid

Q8. Which one of the following has the highest fuel value?
(a) Hydrogen
(b) Charcoal
(c) Natural gas
(d) Gasoline

Q9. The main component of Liquid Petroleum Gas (LPG) are:
(a) Methane, Ethane and Hexane
(b) Methane, Pentane and Hexane
(c) Propane and Butane
(d) Methane, Carbon Monoxide and Hydrogen

Q10. The pH-value for water is-
(a) Nearly zero
(b) Nearly 7
(c) 5 or less than 5
(d) 8.7 or more

Sotutions:

S1. Ans. (b)
Sol. The common composition of solder is 32% Tin, 68% Lead. This combination has a low melting point and is useful for soldering components that are sensitive to heat.

S2. Ans.(a)
Sol. Soap is a comzbination of animal fat or plant oil and caustic soda. Many vegetable fats including olive oil, palm kernel oil and coconut oil are also used in soap making.

S3. Ans.(b)
Sol. Milk contains a sugar called lactose. It also contains harmless bacteria called lactobacillus, which uses glucose for energy and creates lactic acid as a by-product. It is the lactic acid which makes the milk sour. The presence of lactic acid or lactate in milk is due to the fermentation of lactose caused mainly by lactic bacteria.

S4. Ans.(c)
Sol. The chemical formula of Sodium Benzoate is NaC7H5O2. It is widely used as food preservative.

S5. Ans.(c)
Sol. Humus usually refers to the natural decay of material such as leaves in the soil’s top layer. It is a dark organic material that forms in the soil when plant and animal matter decays.

S6. Ans.(a)
Sol. Aluminium sulphate is used in ‘foam’ fire extinguishers, which contains radium bicarbonate and aluminium sulphate in separate receptacles on being mixed they form the foam of bubbles of CO2.

S7. Ans.(d)
Sol. Tartaric acid is the predominant organic acid in grapes.

S8. Ans.(a)
Sol. The heating value of a fuel is the amount of heat that is obtained after one gram (1gm) of fuel is burnt completely in air or oxygen. Hydrogen has the highest heating value among all fuels. Hydrogen is used as a rocket fuel and in burner producing high temperature.

S9. Ans.(c)
Sol. LPG is the abbreviation or short form Liquefied Petroleum Gas. Like all fossil fuels, it is a non-renewable source of energy. It is extracted from crude oil and natural gas. The normal components of LPG thus are propane (C_3 H_8 ) and butane (C_4 H_10 ).

S10. Ans.(b)
Sol. The pH value of pure water is 7. Pure water is neutral by nature. The solution with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline.