Download App

Model Paper 2 — Chemistry STD 11 Science — Question

Rajasthan BoardEnglish MediumSTD 11 ScienceChemistryModel Paper 21 Mark
MCQ
Assertion (A): In 285cm there are 3 significant figures.
Reason (R): Zero preceding to first non-zero digit are not significant.
  • A
    Both A and R are true and R is the correct explanation of A.
  • ✓
    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.
✓

Answer

Correct option: B.
Both A and R are true but R is not the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A .
Explanation: All non-zero digits are significant. For example, in 285 cm , there are three significant figures and in 0.25 mL , there are two significant figures.

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 (A) & Reason (B) MCQ" from Model Paper 2→Model Paper 2 — all question types→Chemistry STD 11 Science question papers→Rajasthan Board STD 11 Science question papers→Rajasthan Board question paper generator→

Similar questions

Direction in the following Questions, the Assertion and Reason have been put forward. Read the statements carefully and choose the correct alternative from the following:
  1. Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
  2. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
  3. Assertion is true but Reason is false.
  4. Both Assertion and Reason are false.
Assertion: The molecular orbitals with higher energy is called anti bonding orbitals.
Reason: The anti bonding nature of a molecular orbital is indicated by an asterisk over its designation.
→
Assertion (A): Both 32 g of $SO _2$ and 8 g of $CH _4$ contain the same number of molecules.
Reason (R): Equal moles of two compounds contain the same number of molecules.
→
Assertion (A): In case of isoelectronic ions the ionic size increases with the increase in atomic number.
Reason (R): The greater the attraction of nucleus, greater is the ionic radius.
→
Assertion (A): Sodium extract is made alkaline in the test of sulphur.
Reason (R): On reacting with $FeCl _3$, alkaline sodium extract, gives red colour.
→
In the following questions a statement of assertion (A) followed by a statement of reason (R) is given. Choose the correct option out of the choices given below each question.

Assertion (A): The compound cyclooctane has the following structural formula:

It is cyclic and has conjugated $8\pi$-electron system but it is not an aromatic compound.

Reason (R): (4n + 2) $\pi$-electrons rule does not hold good and ring is not planar.

  1. Both A and R are correct and R is the correct explanation of A.
  2. Both A and R are correct but R is not the correct explanation of A.
  3. Both A and R are not correct.
  4. A is not correct but R is correct.
→
Note: In the following questions a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.
Assertion (A): Sodium chloride formed by the action of chlorine gas on sodium metal is a stable compound.
Reason (R): This is because sodium and chloride ions acquire octet in sodium chloride formation.
  1. A and R both are correct, and R is the correct explanation of A.
  2. A and R both are correct, but R is not the correct explanation of A.
  3. A is true but R is false.
  4. A and R both are false.
→
Note: In the following questions a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.
Assertion (A): It is impossible to determine the exact position and exact momentum of an electron simultaneously.
Reason (R): The path of an electron in an atom is clearly defined.
  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true and R is not the correct explanation of A.
  3. A is true and R is false.
  4. Both A and R are false.
→
Note: In the following questions a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.
Assertion (A): Simple distillation can help in separating a mixture of propan-1-ol (boiling point 97°C) and propanone (boiling point 56°C).
Reason (R): Liquids with a difference of more than 20°C in their boiling points can be separated by simple distillation.
  1. Both A and R are correct and R is the correct explanation of A.
  2. Both A and R are correct but R is not the correct explanation of A.
  3. Both A and R are not correct.
  4. A is not correct but R is correct.
→
Assertion (A): Each side of a cube is measured to be 7.203 m . What is the volume of the cube to appropriate significant figure $373.7 m^3$.
Reason (R): The mass of one mole of a substance in grams is called its average atomic mass.
→
Note: In the following questions a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.
Assertion (A): The empirical mass of ethene is half of its molecular mass.
Reason (R): The empirical formula represents the simplest whole number ratio of various atoms present in a compound.
  1. Both A and R are true and R is the correct explanation of A.
  2. A is true but R is false.
  3. A is false but R is true.
  4. Both A and R are false.
→