Chemistry set 1 MCQs

Practice interactive objective questions for this topic. Select an option to instantly verify your answer and read detailed explanations.

Showing 504 questions
Q.211 The enthalpy of formation for all elements in their standard state is:
A unity
B zero
C negative
D dependent on temperature
Discuss / Board
Q.212 What happens to the boiling point of water when common salt is added to it?
A it decreases
B it increases
C it remains constant
D it first increases then decreases
Discuss / Board
Q.213 Which of the following hydrocarbons is most likely to undergo an addition reaction?
A methane
B ethane
C ethene
D propane
Discuss / Board
Q.214 Which of the following molecules has a linear geometry despite having lone pairs on the central atom?
A becl2
B co2
C xef2
D so2
Discuss / Board
Q.215 The variation of physical and chemical properties of elements with atomic weight was the basis of which periodic table?
A moseley's periodic table
B mendeleev's periodic table
C newlands' octaves
D dobereiner's triads
Discuss / Board
Q.216 During the electrolysis of acidified water, the volume of gas collected at the cathode is:
A half the volume at the anode
B double the volume at the anode
C equal to the volume at the anode
D four times the volume at the anode
Discuss / Board
Q.217 Assertion (A): Glass is considered a supercooled liquid. Reason (R): Glass flows very slowly over time, similar to liquids.
A both a and r are true and r is the correct explanation of a
B both a and r are true but r is not the correct explanation of a
C a is true but r is false
D a is false but r is true
Discuss / Board
Q.218 Which of the following indicators turns pink in a basic solution?
A methyl orange
B litmus paper
C phenolphthalein
D turmeric
Discuss / Board
Q.219 In the extraction of Aluminium (Hall-Heroult process), cryolite is added to alumina to:
A increase the melting point
B lower the melting point and increase conductivity
C act as an oxidizing agent
D remove impurities of iron
Discuss / Board
Q.220 Which of the following transitions in a hydrogen atom emits a photon of the highest frequency?
A n=2 to n=1
B n=3 to n=2
C n=4 to n=3
D n=5 to n=4
Discuss / Board
Q.221 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
Discuss / Board
Q.222 Which among the following is the strongest Lewis acid?
A bf3
B bcl3
C bbr3
D bi3
Discuss / Board
Q.223 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
Discuss / Board
Q.224 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
Discuss / Board
Q.225 The conjugate base of HSO4- is:
A h2so4
B so4 2-
C h3so4+
D oh-
Discuss / Board
Q.226 Which isotope is used in the treatment of blood cancer (Leukemia)?
A iodine-131
B phosphorus-32
C cobalt-60
D sodium-24
Discuss / Board
Q.227 Which gas is used for artificial ripening of green fruits?
A ethylene
B ethane
C carbon dioxide
D acetylene
Discuss / Board
Q.228 Which of the following is the most abundant element in the Earth's crust by weight?
A silicon
B aluminium
C iron
D oxygen
Discuss / Board
Q.229 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
Discuss / Board
Q.230 Which among the following is a non-polar molecule with polar bonds?
A hcl
B nh3
C ccl4
D h2o
Discuss / Board
Q.231 The 'Gold Number' is related to which of the following properties of colloids?
A electrophoresis
B protective power
C coagulation
D tyndall effect
Discuss / Board
Q.232 What is the oxidation number of Chromium in K2Cr2O7?
A +3
B +5
C +6
D +7
Discuss / Board
Q.233 Which of the following fuels has the highest calorific value?
A coal
B petrol
C lpg
D hydrogen
Discuss / Board
Q.234 Which catalyst is used in the manufacture of Sulphuric acid by the Contact process?
A iron
B platinum or vanadium pentoxide
C nickel
D manganese dioxide
Discuss / Board
Q.235 Which law states that at constant temperature, the solubility of a gas in a liquid is directly proportional to its partial pressure?
A boyles law
B charles law
C henrys law
D daltons law
Discuss / Board
Q.236 Bakelite is a polymer of:
A ethylene glycol and phthalic acid
B phenol and formaldehyde
C vinyl chloride
D adipic acid and hexamethylenediamine
Discuss / Board
Q.237 Which of the following is responsible for the 'rotten egg' smell of sewer gas?
A ammonia
B methane
C hydrogen sulphide
D carbon monoxide
Discuss / Board
Q.238 When an iron nail is dipped in copper sulphate solution, the color of the solution changes from blue to green due to the formation of:
A copper oxide
B iron sulphate
C iron oxide
D copper chloride
Discuss / Board
Q.239 Which of the following acids is present in red ants?
A acetic acid
B citric acid
C formic acid
D oxalic acid
Discuss / Board
Q.240 The radioactive element most commonly used in cardiac pacemakers is:
A uranium-235
B plutonium-238
C radium-226
D deuterium
Discuss / Board

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