Two statements are given - one labelled Assertion (A) and the oth… - Vidyadip

MCQ

Two statements are given $-$ one labelled
Assertion $(A)$ and the other labelled
Reason $(R)$. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below:
Assertion $(A):$ In a homologous series of alcohols, the formula for the second member is $C _2 H _5 OH$ and the third member is $C _3 H _7 OH$.
Reason$(R):$ The difference between the molecular masses of the two consecutive members of a homologous series is $144 .$

A
Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
B
Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
✓
$A$ is true, but $R$ is false.
D
$A$ is false, but $R$ is true.

✓

Answer

Correct option: C.

$A$ is true, but $R$ is false.

A homologous series is a series of organic compounds that contains identical functional group and differs only in the length of the carbon chain in the compound.
The general formula for homologous series for alcohols is $C ( n ) H (2 n +1) OH$, where $n$ is a natural number.
Substituting $n=2$ and $n=3$ we get $C _2 H _5 OH$ and $C _3 H _7 OH$ respectively, which verifies the assertion made.
The two consecutive members of the homologous series varies only by a $CH _2$ group, hence the difference in molecular mass of two consecutive members is equal to $14 .$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Assertion - Reasoning (1 Marks)" from Carbon and its Compounds→Carbon and its Compounds — all question types→Science STD 10 question papers→CBSE Board STD 10 question papers→CBSE Board question paper generator→

Similar questions

For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : The reaction during which hydrogen is lost is called oxidation reaction.
Reason : Reducing agent removes hydrogen from another substance.

For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Using jute bags while shopping is more environment friendly as compared to polythene bags.
Reason : Jute is biodegradable, whereas polythene bag is non $-$ biodegradable.

For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : An ecosystem consists of a living biological community and its non $-$ living environment.
Reason : Ecosystem functions as self $-$ sufficient or independent unit in nature.

For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Sexual reproduction leads to greater variety in population.
Reason : Sexual reproduction plays an important role in the origin of new species.

For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : A bird perches on a high $-$ power line and nothing happens to the bird.
Reason : The circuit is incomplete for the bird sitting on high-power line.

For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : The flow of energy in a food chain operating in an ecosystem is always unidirectional.
Reason : Lots of energy is lost as heat from living organisms at each trophic level of a food chain.

Assertion (A): On adding dil. HCI to a test tube containing a substance 'X', a colourless gas is produced which gives a pop sound when a burning match stick is brought near it.
Reason (R): In this reaction metal 'X' is displaced by Hydrogen

In the following questions, a statement of Assertion is given by the corresponding statement of Reason. Of the statements, mark the correct answer as
Assertion : Biotic components of an ecosystem include all the living organisms present in that ecosystem.
Reason : Biotic components also include wind, gases, light, etc.

For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Zinc reacts with sulphuric acid to form zinc sulphate and hydrogen gas and it is a displacement reaction.
Reason : Zinc reacts with oxygen to form zinc oxide.

Assertion (A): The strength of the magnetic field produced at the centre of a current-carrying circular coil
increases on increasing the number of turns of the circular coil.
Reason (R): Magnetic field strength is directly proportional to the number of turns of the circular coil.