General Science Jkssb Chemistry Set 1 Mcqs (504 MCQs) | JKSSB & SSC Quiz

General Science

jkssb chemistry set 1 mcqs

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Practice Questions

504 Total
Question 221 Discuss
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The primary cause of the temporary hardness of water is the presence of:

A
magnesium sulphate
B
calcium chloride
C
calcium bicarbonate
D
sodium carbonate

Answer & Explanation

Correct Option: C

Temporary hardness is caused by dissolved bicarbonates of calcium and magnesium, which can be removed by boiling.
Question 222 Discuss
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Which among the following is the strongest Lewis acid?

A
bf3
B
bcl3
C
bbr3
D
bi3

Answer & Explanation

Correct Option: D

BI3 is the strongest Lewis acid because back-bonding is least effective between Boron (2p) and Iodine (5p) orbitals.
Question 223 Discuss
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In an adiabatic process, the work done by the system is at the expense of its:

A
enthalpy
B
internal energy
C
entropy
D
temperature only

Answer & Explanation

Correct Option: B

In an adiabatic process (q=0), ΔU = -W. Work done by the system reduces its internal energy, causing cooling.
Question 224 Discuss
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Which of the following organic compounds is used as a 'sweetening agent' and also in the manufacture of explosives?

A
ethanol
B
glycerol
C
methanol
D
glycol

Answer & Explanation

Correct Option: B

Glycerol is used in foods and reacts with nitric acid to form Nitroglycerin, a powerful explosive.
Question 225 Discuss
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The conjugate base of HSO4- is:

A
h2so4
B
so4 2-
C
h3so4+
D
oh-

Answer & Explanation

Correct Option: B

A conjugate base is formed when an acid loses a proton (H+). HSO4- minus H+ equals SO4 2-.
Question 226 Discuss
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Which isotope is used in the treatment of blood cancer (Leukemia)?

A
iodine-131
B
phosphorus-32
C
cobalt-60
D
sodium-24

Answer & Explanation

Correct Option: B

Phosphorus-32 is used to treat polycythemia vera and certain types of leukemia.
Question 227 Discuss
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Which gas is used for artificial ripening of green fruits?

A
ethylene
B
ethane
C
carbon dioxide
D
acetylene

Answer & Explanation

Correct Option: A

Ethylene is a natural plant hormone; Acetylene (from calcium carbide) is also used but Ethylene is the primary biological ripening agent.
Question 228 Discuss
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Which of the following is the most abundant element in the Earth's crust by weight?

A
silicon
B
aluminium
C
iron
D
oxygen

Answer & Explanation

Correct Option: D

Oxygen makes up about 46.6% of the Earth's crust by weight, followed by Silicon (27.7%).
Question 229 Discuss
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The rate of a chemical reaction generally doubles for every 10 degree rise in temperature. This is due to:

A
increase in collision frequency
B
decrease in activation energy
C
increase in the fraction of effective collisions
D
lowering of threshold energy

Answer & Explanation

Correct Option: C

A rise in temperature increases the number of molecules having energy greater than or equal to the activation energy.
Question 230 Discuss
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Which among the following is a non-polar molecule with polar bonds?

A
hcl
B
nh3
C
ccl4
D
h2o

Answer & Explanation

Correct Option: C

C-Cl bonds are polar, but the symmetrical tetrahedral shape of CCl4 causes the dipole moments to cancel out.
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