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Chemistry MCQ: Questions and Answers for Competitive Exams
Welcome to our Chemistry MCQ section — one of the most comprehensive collections of chemistry questions and answers designed specifically for students preparing for UPSC, SSC, NDA, and other competitive examinations. Chemistry is a subject that demands both conceptual clarity and factual precision, and our carefully crafted multiple choice questions cover every important topic — from atomic structure and chemical bonding to organic chemistry, periodic table, acids and bases, and everyday chemical reactions. Each question comes with a detailed explanation written in a simple, teacher-like style to help you not just memorise the answer but genuinely understand the concept behind it.
What mass and charge do Gamma rays Have?
zero mass and no charge
zero mass and positive charge
unit mass and zero charge
unit mass and negative charge
What Is the Chemical name of Aspirin used as pain reliever?
Acetyle salicylate
Acetylsalicylic acid
Methyl salicylate
Methyl salicylic acid
Which one of the following chemical substances exists as a gas under ordinary conditions and room temperature?
CI4
CF4
CCI4
CBr4
Which one of the following is the oxidation state of oxygen in OF2?
+2
-2
+1
-1
What is the Chemical part of a dye that Absorbs Light and Produces Colour?
neon
a chromophore
a photochrome
a pigment
Which one of the following is a mixture?
Diamond
Table salt
Sugar
Sea Water
How is an Element best characterized?
electronic configuration
atomic number
atomic weight
atomic volume
Which one of the following is used as a filler in rubber tyres?
Graphite
Carbon black
Coke
Coal
Consider the following statements:
Ammonia is
1. readily soluble in water.
2. used as a refrigerant.
3. used for preparation of polypropylene.
4. used as an additive in cooking gases.
Which of these statements are correct?
1 and 2
2 and 4
3 and 4
1 and 3
Dry ice is —
super-cooled ice
solid water with zero humidity
solid carbon dioxide
solidified ammonia
The volume of 1 N sodium hydroxide required to neutralise 10 ml of 0.5N hydrochloric acid will be
5 ml.
10 ml.
15 ml.
20 ml.
A mixture of ethyl alcohol and water can be separated into individual components by
separation of layers in a separatory funnel
crystallisation
chromatography
fractional distillation
In order to prevent corrosion, iron pipes are often coated with a layer of zinc. This process is known as
Electroplating
Annealing
Galvanisation
Vulcanisation
Positive rays in a discharge tube with perforated cathode travel
parallel to the anode
parallel to the cathode
from cathode to anode
from anode to cathode
Which one of the following has the lowest percentage of carbon?
Mild steel
Soft steel
Hard steel
Wrought iron
The reaction of zinc with dilute sulphuric acid produces
hydrogen
sulphur dioxide
sulphur trioxide
hydrogen sulphide
In a spontaneous process —
entropy change is positive
entropy change is negative
there is no change in entropy
entropy and free energy changes are positive
If the temperature of a semiconductor is raised, its resistivity will
increase
decrease
remain constant
reduce to zero