Can anyone give me assertion and reasoning for 9th chapter 2 : Is Matter Around Us Pure
Answers
OPTIONS:
(a) Both A and R are true and R is the correct explanation of the assertion.
(b) Both A and R are true but R is not the correct explanation of the assertion.
(c) A is true but R is false.
(d) A is false but R is true.
QUESTIONS:
1. Assertion (A) : The air is a compound containing oxygen, nitrogen, argon, carbon dioxide and water vapour in a fixed proportion according to their masses.
Reason (R) : A compound is a substance whose composition of the components is fixed Le; they combine together in a fixed ratio according to their masses.
2. Assertion (A) :A solution is a homogeneous mixture of two or more substances. Reason (R) : A solution has a solvent and a solute as its components.
3. Assertion (A) : In a colloid, the size of solute particles is bigger than the particles of true solution but smaller than those of suspension.
Reason (R) : Sand with particle size between 10" to 10 m dissolves in water to form colloidal solution that shows Tyndall effect. (1 Mark)
4. Assertion (A) : Chromatography is used to separate pigments from natural colours like chlorophyll.
Reason (R) : Coloured components of a mixture can be separated by using an adsorbent on which they are adsorbed at different rates.
5. Assertion (A) : A mixture of acetone and water is separated by using simple distillation method. This method is used to separate two or more miscible liquids.
Reason (R) : Acetone, out of the two components has a lower boiling point and water has higher boiling point.
6. Assertion (A) : Rusting of iron is a chemical change.
Reason (R) : Rusting is a slow process in which the surface of iron is spoiled due to the action of oxygen and water on it.
7. Assertion (A) :A solution of table salt in a glass of water is homogeneous.
Reason (R) : A solution having different composition throughout is homogeneous.
8. Assertion (A): A mixture of acetone and methanol can be separated by fractional distillation. Reason (R) : The difference between their boiling points is very less.
9. Assertion (A) : Impure benzoic acid can be purified by sublimation. Reason (R) : Benzoic acid sublimes on heating.
COMPLETE QUESTION:-
Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.
ANSWER:
Assertion and reasoning for 9th chapter 2 : Is Matter Around Us Pure are listed as follows:-
Q.1. Assertion: When a light beam is passed through a colloidal solution in a dark environment, the path of the beam becomes visible.
Reason: for this is that colloidal particles scatter light.
Solution: (a) Assertion (A) and reason (R) are both true, and reason (R) is the correct explanation for assertion (A) (A).
Colloidal particles scatter light, revealing the path of the beam.
Q.2 Assertion: A mixture of benzoic acid and naphthalene can be separated from water by crystallisation.
Reason: While benzoic acid is soluble in hot water, naphthalene is not.
Solution: (a) Both assertion (A) and reason (R) are true, and reason (R) is the appropriate explanation for assertion (A) (A).
Naphthalene does not dissolve in hot water, but benzoic acid does.
Q.3 Assertion: A table salt solution in a glass of water is homogeneous.
Reason: A homogeneous solution has a different composition throughout.
Soloution: (c) Assertion (A) is correct, but reason (R) is incorrect.
A homogeneous solution has the same composition throughout.
Q.4 Assertion: By shaking with ether, a mixture of sugar and benzoic acid can be separated.
Reason: is that sugar is insoluble in water.
Solution: (c) Assertion (A) is correct, but reason (R) is incorrect.
Sugar dissolves in water but not in ether.
Q.5. Assertion: Sublimation occurs when a substance changes from solid to vapour without passing through the liquid state, and vice versa.
Reason: Distillation entails two processes: vaporisation and condensation.
Solution: (b) Although both assertion (A) and reason (R) are true, reason (R) is not the correct explanation for assertion (A) (A).
Both define sublimation and distillation, respectively.
Q.6.Assertion: The true solution exhibits the Tyndall effect.
Reason: Particles are extremely large in size.
Solution: : (d) While assertion (A) is false, reason (R) is correct.
Because the particle size is too small to scatter light, true solutions do not exhibit the Tyndall effect.
Q.7. Assrertion: Colloidal solutions are stable, and colloidal particles do not settle.
Reason: The force of gravity acting on colloidal particles is countered by Brownian movement.
Solution: (a) Assertion (A) and reason (R) are both true, and reason (R) is the correct explanation for assertion (A) (A).
Colloidal particles do not settle because of the constant movement of particles.
Q.8. Assertion: A table salt solution in a glass of water is homogeneous.
Reason: A homogeneous solution has a different composition throughout.
Solution: (c) Assertion (A) is correct, but reason (R) is incorrect.
A homogeneous solution itself has the same composition throughout.
Q.9 Assertion: Sublimation can be used to purify impure benzoic acid.
Reason : is that when heated, benzoic acid sublimes.
Solution: (a) Assertion (A) and reason (R) are both true, and reason (R) is the correct explanation for assertion (A) (A).
Impurities do not sublime when heated, whereas benzoic acid does.
Q.10 Assertion: The Tyndall effect is a type of optical property.
Reason: for this is that electrophoresis is an electrical property.
Solution: (b) Although both assertion (A) and reason (R) are true, reason (R) is not the correct explanation for assertion (A) (A).
Light scattering by colloidal particles is an optical activity. Colloidal particle coagulation in an electrical field is an electrical property.