Logical Reasoning · Statements & Arguments
Assertion and Reason — Questions & Answers
Assertion and reason questions give two statements and ask whether each is true and whether the reason explains the assertion. Check each statement's truth first, then the link.
- 5 solved questions
- Step-by-step AI walkthroughs
- How-to-approach tips
How to approach
Take three steps. 1) Is A true? 2) Is R true? 3) Only if both are true: does R answer "why is A true?" Then pick the option that matches.
Ask "why is A true?" and look for the option that answers it. It must be true AND explain A.
Check each pair: A true, R true, and R explains A. Exactly one pair passes all three.
5 solved Assertion and Reason questions
Assertion (A): Ice floats on water.
Reason (R): Ice is less dense than liquid water.
Which option correctly describes A and R?Solution — answer A
Explains. Both are true, and ice floats precisely because it is less dense than the water it floats in.
4 steps · reveal one at a timeStep 1: Evaluate Assertion (A)
Consider the first statement: "Ice floats on water." Think about what you observe in daily life. Does ice sink or float in a glass of water? This statement is a true observation.
Step 2: Evaluate Reason (R)
Now, look at the second statement: "Ice is less dense than liquid water." This is a fundamental property of water. When water freezes, its molecules arrange into a crystalline structure, making it less dense than its liquid form. This statement is also true.
Step 3: Connect A and R
We've established that both A and R are true. Now, consider if R explains A. An object floats in a liquid if its density is less than that of the liquid. So, ice being less dense than water directly explains why it floats.
Step 4: The answer
So the answer is (A) A and R are both true, and R correctly explains A. Both statements are true, and the lower density of ice is precisely why it floats on water.
Assertion (A): Deep-sea divers carry cylinders of air.
Which of these is the correct reason for the assertion?Solution — answer C
Divers need a supply of air because they cannot breathe the air they need from the water. Heavy cylinders and breathing out carbon dioxide are true but explain nothing, and sea water does contain dissolved oxygen.
4 steps · reveal one at a timeStep 1: Understand the Need
The question asks why deep-sea divers carry cylinders of air. We need to think about what humans need to breathe and how that applies underwater.
Step 2: Human Breathing
Humans require a continuous supply of oxygen to live. On land, we get this oxygen from the air around us, which our lungs are perfectly adapted to process.
Step 3: Breathing Underwater
Even though seawater contains some dissolved oxygen, human lungs are not designed to extract it from water. We cannot breathe water like fish do with gills; our bodies need air.
Step 4: The Answer
So the answer is (C) Divers cannot breathe the air they need from the water around them. This is the primary reason divers must carry their own supply of breathable air.
Look at these four assertion–reason pairs.
In which pair is R true AND the correct explanation of A?Solution — answer A
The paint pair: both true, and keeping air and moisture away from the iron is exactly how paint stops rusting. In the glass pair R doesn't explain A, 'iron is lighter than wood' is false, and copper does not rust.
4 steps · reveal one at a timeStep 1: Understand the Goal
We need to find the pair where the Reason (R) is not only true, but also provides the correct scientific explanation for the Assertion (A). Both conditions must be met for a pair to be correct.
Step 2: Evaluate Rusting Pair
Consider the statement: 'Paint protects iron gates from rusting.' This is true. The reason given is: 'Paint keeps air and moisture away from the iron.' This is also true, and it's precisely how paint prevents rust. Rusting requires both air (oxygen) and moisture.
Step 3: Check Other Pairs
For the glass pair, glass being made from sand doesn't explain its transparency. For the iron pair, iron is actually heavier than wood, so the reason is false. For the copper pair, copper does not rust quickly; it tarnishes, which is different from rusting.
Step 4: The answer
So the answer is (A) A: Paint protects iron gates from rusting. R: Paint keeps air and moisture away from the iron. Both the assertion and the reason are true, and the reason correctly explains the assertion.
Assertion (A): Plants give out oxygen during photosynthesis.
Reason (R): During photosynthesis, plants take in oxygen and give out carbon dioxide.
Which option correctly describes A and R?Solution — answer C
R is false. A is true, but R has it backwards: in photosynthesis plants take in carbon dioxide and give out oxygen.
4 steps · reveal one at a timeStep 1: Evaluate Assertion A
Let's look at Assertion (A): "Plants give out oxygen during photosynthesis." Recall what you know about the process of photosynthesis. Is this statement accurate?
Step 2: Evaluate Reason R
Now, consider Reason (R): "During photosynthesis, plants take in oxygen and give out carbon dioxide." Think about the gases involved in photosynthesis. Does this statement correctly describe the gas exchange?
Step 3: Determine Truth Values
Assertion (A) is true; plants do release oxygen during photosynthesis. However, Reason (R) is false. During photosynthesis, plants take in carbon dioxide and release oxygen, not the other way around.
Step 4: The answer
So the answer is (C) A is true, but R is false. Assertion (A) correctly states a fact about photosynthesis, while Reason (R) incorrectly describes the gas exchange.
Assertion (A): Wet clothes dry faster on a windy day.
Which reason is true AND explains the assertion?Solution — answer A
Wind carries the water vapour away, which speeds up evaporation. The cotton fact is true but irrelevant, and the other two are false.
4 steps · reveal one at a timeStep 1: Understand Drying
When wet clothes dry, water turns into water vapour and moves into the air. This process is called evaporation. The faster evaporation happens, the quicker the clothes dry.
Step 2: Wind's Effect
On a windy day, the air around the clothes is constantly replaced. Wind blows away the air that has already absorbed some water vapour from the clothes.
Step 3: Speeding Evaporation
By removing the humid air, wind ensures that drier air is always in contact with the clothes. This allows more water molecules to evaporate from the clothes into the air, speeding up the drying process.
Step 4: The answer
So the answer is (A) Wind carries water vapour away, which speeds up evaporation. This statement accurately explains why clothes dry faster on a windy day by enhancing evaporation.
Free to start
Get exam-ready on Assertion and Reason
Generate fresh assertion and reason practice sets in Test Studio, get step-by-step AI explanations the moment you slip, and close the gaps in Socrative Mode.
- Step-by-step AI solutions
- Fresh practice sets on demand
- Guided Socrative Mode drills