A. HI
B. HF
C. HCI
D. HBr
✅ The correct answer is option B.
Chemistry MCQs
32. The mass number of an atom is equal to
A. the number of protons
B. the number of protons and electrons
C. the number of nucleons
D. the number of neutrons
✅ The correct answer is option C.
33. The most extensive, commercially useful source of thorium as monazite sand occurs in India at
A. Orissa coast
B. Travancore coast
C. West Bengal coast
D. Gujarat coast
✅ The correct answer is option B.
34. The most abundant rare gas in the atmosphere is
A. He
B. Ne
C. Ar
D. Xe
✅ The correct answer is option C.
35. The material which can be deformed permanently by heat and pressure is called a
A. thermoplastic
B. thermoset
C. chemical compound
D. polymer
✅ The correct answer is option B.
36. The formula C6H5-CO-CH3 represents
A. Acetone
B. Acetic acid
C. Acetophenone
D. Phenyl acetate
✅ The correct answer is option C.
37. The half life period of an isotope is 2 hours. After 6 hours what fraction of the initial quantity of the isotope will be left behind?
A. 01-Jun
B. 01-Mar
C. 01-Aug
D. 01-Apr
✅ The correct answer is option C.
38. The maximum number of isomers for an alkene with molecular formula C4H8 is
A. 5
B. 4
C. 2
D. 3
✅ The correct answer is option B.
39. The hottest part of the gas flame is known as
A. luminous zone
B. dark zone
C. blue zone
D. non-luminous zone
✅ The correct answer is option D.
40. What are the number of moles of CO2 which contains 16 g of oxygen?
A. 0.5 mole
B. 0.2 mole
C. 0.4 mole
D. 0.25 mole
✅ The correct answer is option A.
One mole of CO2 has mass of 44 g and 32 g of O2. So 16 g of O2 have 22 g of CO2 or 0.5 moles of it.
One mole of CO2 has mass of 44 g and 32 g of O2. So 16 g of O2 have 22 g of CO2 or 0.5 moles of it.