chemistry assertion and reason type question for class 10 ch1
Answers
Explanation:
hlo mate here's your answer
Assertion and Reasoning based questions are a bit tricky. You should be able to distinguish whether the assertion is well connected to the reason or these are just random facts. Read both statements carefully, and check if both statements are factually or logically correct or not. If both are correct, then try to check if both are well connected to each other or not.
The questions below consist of statements of an Assertion and a Reason. Use the following key to choose an appropriate answer:
(A) If both assertion and reason are CORRECT and the reason is the CORRECT explanation of the assertion.
(B) If both assertion and reason are CORRECT, but the reason is NOT THE CORRECT explanation of the assertion.
(C) If assertion is CORRECT, but reason is INCORRECT
(D) If assertion is INCORRECT, but reason is CORRECT
QUESTIONS:
1. ASSERTION: Combustion reactions are also called exothermic oxidation reactions.
REASON: In these reactions, oxygen is added and heat energy is released.
2. ASSERTION: Sodium and potassium is stored under kerosene.
REASON: Sodium (Na) and Potassium (K) belongs to group IA, so they are alkali metals.
3. ASSERTION: Aluminium oxide is an amphoteric oxide.
REASON: They react with acid as well as base to form salt and water.
4. ASSERTION: Isotopes have same atomic masses.
REASON: Isotopes have same atomic number and have similar chemical properties.
5. ASSERTION: Metallic character decreases across a period.
REASON: Metals are electro-negative.
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6. ASSERTION AND REASON
DIRECTION : Each of these questions contains an Assertion
followed by Reason. Read them carefully and answer the
question on the basis of following options. You have to select
the one that best describes the two statements.
(a) If both Assertion and Reason are correct and
Reason is the correct explanation of Assertion.
(b) If both Assertion and Reason are correct, but
Reason is not the correct explanation of Assertion.
(c) If Assertion is correct but Reason is incorrect.
(d) If Assertion is incorrect but Reason is correct
1. Assertion : Stannous chloride is a powerful oxidising
agent which oxidises mercuric chloride to mercury.
Reason : Stannous chloride gives grey precipitate with
mercuric chloride, but stannic chloride does not do so.
Ans : (c) If Assertion is correct but Reason is incorrect.
2. Assertion : Corrosion of iron is commonly known as
rusting.
Reason : Corrosion of iron occurs in presence of water
and air.
Ans : (b) If both Assertion and Reason are correct,
but Reason is not the correct explanation of
Assertion.
Corrosion occurs due to oxidation of iron.
3. Assertion : In a reaction.
Zn s CuSO aq ZnSO aq Cu s () ( ) ( ) () + + 4 4 $ Zn is a reductant but itself get oxidized.
Reason : In a redox reaction, oxidant is reduced by
accepting electrons and reductant is oxidized by losing
electrons.
Ans : (a) If both Assertion and Reason are correct and
Reason is the correct explanation of Assertion.
4. Assertion : A reducing agent is a substance which can
either accept electron.
Reason : A substance which helps in oxidation is
known as reducing agent.
Ans : (d) If Assertion is incorrect but Reason is correct
A reducing agent is a substance which oxidizes itself
but reduces others i.e., looses electrons.
5. Assertion : The balancing of chemical equations is
based on law of conservation of mass.
Reason : Total mass of reactants is equal to total mass
of products.
Ans : (a) If both Assertion and Reason are correct and
Reason is the correct explanation of Assertion.
6. Assertion (A) : Carbon dioxide turns lime water milky.
Reason (R) : Carbon dioxide sullies the water.
Ans : (c) Assertion (A) is true but reason (R) is false.
Carbon dioxide reacts with lime water (calcium
hydroxide) to form milky precipitate of calcium
carbonate.
7. Assertion (A) : A chemical reaction becomes faster at
higher temperatures.
Reason (R) : At higher temperatures, molecular
motion becomes more rapid.
Ans : (a) Both assertion (A) and reason (R) are true
and reason (R) is the correct explanation of
assertion (A).
Both A and R are true and R is the correct explanation
of (A). A chemical reaction becomes faster at higher
temperatures because at high temperature, the
movement of particles are greater.
8. Assertion (A) : Sodium metal is stored under Kerosene.
Reason (R) : Metallic sodium melts when exposed to
air.
Ans : (c) Assertion (A) is true but reason (R) is false.
Sodium is a very reactive metal. It is kept in kerosene
to prevent it from coming in contact with oxygen and
moisture present. If this happens, it will react with the
moisture present in air and form sodium hydroxide.
This is a strongly exothermic reaction, and lot of heat
is generated.