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Chemistry Top MCQs – 6

The main buffer system of the human blood is
(A) H2CO3 – HCO3
(B) H2CO3 – CO32-
(C) CH3COOH – CH3COO-
(D) NH2CONH2 – NH2CONH+
Answer: Option A

The octane number of zero is assigned to
(A) 2-methyl octane
(B) n-heptane
(C) iso-octane
(D) 3-methyl octane
Answer: Option B

The nuclear particles which are assumed to hold the nucleons together are
(A) Electrons
(B) Positrons
(C) Neutrons
(D) Mesons
Answer: Option D
The number of waves in n × 10th Bohr’s orbit are
(A) n2
(B) n
(C) n-2
(D) n3
Answer: Option B

The gas used for artificial ripening of green fruit is
(A) Ethylene
(B) Ethane
(C) Carbon dioxide
(D) Acetylene
Answer: Option A

The number of g-molecule of oxygen in 6.02 × 1024CO molecules is
(A) 1 gram of molecule
(B) 0.5 gram of molecule
(C) 5 gram of molecule
(D) 10 gram of molecule
Answer: Option C

The number of electrons presents in H+ is
(A) Zero
(B) One
(C) Two
(D) Three
Answer: Option A

The number of waves made by an electron moving in an orbit having maximum magnetic quantum number is +3
(A) 4
(B) 5
(C) 2
(D) 0
Answer: Option A

The method of concentrating the ore which makes use of the difference in density between ore and impurities is called
(A) Liquation
(B) Leaching
(C) Levigation
(D) Magnetic separation
Answer: Option C

The metallurgical process in which a metal is obtained in a fused state is called
(A) Smelting
(B) Roasting
(C) Calcinations
(D) Froth floatation
Answer: Option A