Chemistry Questions for NDA: 27th August

Dear Aspirants, Chemistry is an important subject in various exams like NDA, CDS, AFCAT, CAPF and other Police Exams. Here at Defence Adda we provide you with the quizzes based on the syllabus and pattern of these exams. The questions asked are of 10+2 level and preparing with a wide variety of questions will help you ace in these exams. Here is a quiz based on the latest syllabus of these exams based on topics like Metals, Non-metals, Oxidation and Reduction, Periodic Table etc to help you prepare with a wide variety of questions. 

Q1. The poisonous gas accidentally released in Bhopal Gas Tragedy is -
(a) Methane
(b) Nitrous Oxide
(c) Methyl Isocyanate
(d) Cyanogen

Q2. Release of which among the following is the primary reason for depletion of the ozone layer?
(a) Nitrous oxide
(b) Hydrogen dioxide
(c) Chlorofluro carbon
(d) Carbon monoxide

Q3. Which of the following molecules is joined by a double covalent bond?
(a) Cl2
(b) O2
(c) N2
(d) He

Q4. Which of the following elements has the lowest melting point?
(a) Iodine
(b) Lead
(c) Tin
(d) Mercury

Q5. The common name of sodium bicarbonate is _____.
(a) Baking soda
(b) Borax
(c) Bleach
(d) Epsom salt

Q6. Metals react with sodium hydroxide to produce ___________.
(a) Oxygen gas
(b) Sodium
(c) Water
(d) Hydrogen gas

Q7. Which base is present in lime water?
(a) Sodium hydroxide
(b) Magnesium hydroxide
(c) Calcium hydroxide
(d) Ammonium hydroxide

Q8. Rusting is _____.
(a) Electrolysis
(b) Oxidation
(c) Redox
(d) Reduction

Q9. Which amongst the following is not a Cation?
(a) Aluminium ion
(b) Copper ion
(c) Sulphate ion
(d) Zinc ion

Q10. Which of the following is not a component of Smog?
(a) Volatile organic compounds
(b) Nitrogen Oxide
(c) Sulphur dioxide
(d) Chlorine oxide


S1. Ans.(c)
Sol. Bhopal gas tragedy occured on the night of 2–3 December 1984 at the Union Carbide India Limited (UCIL) pesticide plant in Bhopal, Madhya Pradesh. Over 500,000 people were exposed to methyl isocyanate (MIC) gas and other chemicals leaked from UCIL.

S2. Ans.(c)
Sol.The Chlorofluro carbon formed by chlorine, fluorine and carbon. They are often used as refrigerants, solvents, and for the manufacture of spongy plastics. It is the primary reason for depletion of the ozone layer.

S3. Ans.(b)
Sol. Oxygen atom is joined by double covalent bond.

S4. Ans.(d)
Sol. Mercury has the lowest melting point. Mercury has a melting point of -37.89F.

S5. Ans.(a)
Sol. Sodium bicarbonate is commonly known as baking soda. It is a chemical compound with the formula NaHCO3.

Sol. Sodium hydroxide reacts with metal to release hydrogen gas. The metal takes the oxygen atom from sodium hydroxide, which in turn takes the oxygen atom from the water, and releases the two hydrogen atoms. The reaction thus produces hydrogen gas.

Sol. Calcium hydroxide base is present in lime water.

Sol. Redox reaction is the reaction in which oxidation and reduction occurs simultaneously. Rust of iron is nothing but hydrate of iron oxide and iron (III) oxide -hydroxide.

Sol. A cation is a positively-charged ion, while an anion is negatively charged. Sulphate is an anion.

Sol. Smog is a type of air pollutant. It  is composed of nitrogen oxides, sulphur oxides, ozone, smoke or particulates among others (less visible pollutants include carbon monoxide, CFCs and radioactive sources).

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