Solutions, Suspensions and Colloids Questions in English

(C) '$C$' has made the desired solution.
The formula for mass by volume percentage is:
$\text{Mass by volume } \% = \frac{\text{Mass of solute (g)}}{\text{Volume of solution (mL)}} \times 100$
For student '$C$':
$\text{Mass by volume } \% = \frac{50\, g}{100\, mL} \times 100 = 50\%$
Student '$A$' prepared a solution where the total volume is likely greater than $100\, mL$ (as $50\, g$ of $NaOH$ occupies volume),and student '$B$' prepared a mass by mass solution,not mass by volume.

(N/A) Fog: Dispersed phase is liquid and dispersing medium is gas.
$(b)$ Cheese: Dispersed phase is liquid and dispersing medium is solid.
$(c)$ Coloured gemstone: Dispersed phase is solid and dispersing medium is solid.

(N/A) The difference based on particle size is as follows:

Type of Mixture	Particle Size
True Solution	$< 1 \, nm$
Colloidal Solution	$1 - 100 \, nm$
Suspension	$> 100 \, nm$

$(b)$ To test if the solution is saturated or unsaturated,add a small amount of additional sodium chloride to the solution at the same temperature. If the added salt dissolves,the original solution was unsaturated. If the added salt does not dissolve and settles at the bottom,the original solution was saturated.
$(c)$ The solubility of most solid solutes in a liquid solvent increases with an increase in temperature. Therefore,by heating the solution,we can increase the solubility and dissolve more solute.

(N/A) Mass of solute $(w) = 34.2\, g$
Mass of solution $(W) = 214.2\, g$
Concentration of sugar in the syrup $= \frac{\text{Mass of solute}}{\text{Mass of solution}} \times 100$
$= \frac{34.2}{214.2} \times 100 = 15.96\%$
$(b)$ $A$ solution is a homogeneous mixture of two or more substances.

(N/A) Let the mass of potassium chloride required be $x \, g$.
The mass of the solution is $(x + 100) \, g$.
Given that the concentration is $40 \%$,we use the formula:
$\text{Concentration} = \frac{\text{Mass of solute}}{\text{Mass of solution}} \times 100$
$40 = \frac{x}{x + 100} \times 100$
$40(x + 100) = 100x$
$40x + 4000 = 100x$
$60x = 4000$
$x = \frac{4000}{60} = 66.67 \, g$
$(b)$ Solubility is defined as the maximum amount of solute that can be dissolved in a given amount of solvent at a specific temperature to form a saturated solution.
Effect of temperature:
$1$. For most solid solutes,solubility increases with an increase in temperature.
$2$. For gaseous solutes,solubility generally decreases with an increase in temperature.

(N/A) Properties of colloids:
$(a)$ $A$ colloid is a heterogeneous mixture. The size of particles of a colloid is too small to be individually seen by the naked eye.
$(b)$ Colloidal particles are big enough to scatter a beam of light passing through them and make the path of light visible (Tyndall effect).
$(c)$ They do not settle down when left undisturbed,i.e.,a colloid is quite stable. However,centrifugation techniques can be used to separate the colloidal particles.
Categorization of examples:
- Jelly: Gel
- Fog: Aerosol
- Milk: Emulsion
- Shaving cream: Foam

(N/A) Differences between suspension and true solution:

Suspension	True solution
$(i)$ Opaque in nature.	$(i)$ Transparent in nature.
$(ii)$ Particles can be separated by filtration.	$(ii)$ Particles cannot be separated by filtration.
$(iii)$ Unstable; particles settle down on keeping.	$(iii)$ Stable; particles do not settle down.

$(b)$ Colloids from the given list are: Milk,smoke,butter,and face cream.

(N/A) The differences are tabulated below:

Property	Suspension	True Solution
$(i)$ Filtration	Particles can be separated by filtration.	Particles cannot be separated by filtration.
$(ii)$ Transparency	Opaque.	Transparent.
$(iii)$ Stability	Unstable (particles settle down).	Stable (particles do not settle).

$(b)$ Two examples of the Tyndall effect in daily life are:
$(i)$ $A$ beam of light entering a dark room through a small hole,making dust particles visible.
$(ii)$ Sunlight passing through the canopy of a dense forest,where tiny water droplets in the mist scatter the light.

(C) The three characteristics of a colloid are:
$(i)$ It is a heterogeneous mixture.
$(ii)$ The particles of a colloid scatter a beam of light passing through it (Tyndall effect).
$(iii)$ It is a stable mixture,meaning the particles do not settle down when left undisturbed.
$(b)$ The two components of a colloid are:
$(i)$ Dispersed phase
$(ii)$ Dispersing medium
$(c)$ Among the given mixtures,the colloids are: Ink,blood,and foam.

(C) Colloids are heterogeneous mixtures where the particle size is intermediate between true solutions and suspensions $(1-1000 \ nm)$. They appear homogeneous but are actually heterogeneous. Suspensions are heterogeneous mixtures where the solute particles do not dissolve but remain suspended throughout the bulk of the medium and are large enough to be seen by the naked eye $(> 1000 \ nm)$.
From the given list:
$1$. Soda water: Solution.
$2$. Milk: Colloid.
$3$. Sponge: Colloid (solid foam).
$4$. Clouds: Colloid (aerosol).
$5$. Mixture of alcohol and water: Solution.
$6$. Jelly: Colloid (gel).
Therefore,the colloids are: Milk,sponge,clouds,and jelly.

(N/A) Concentration of a solution is the amount of solute present in a given amount of solvent or solution at a specific temperature.
Solubility is the maximum amount of solute that can be dissolved in a given amount of solvent at a specific temperature to form a saturated solution.

(N/A) $(i)$ When a saturated solution is heated,its solubility increases,making it capable of dissolving more solute. Consequently,the solution becomes unsaturated.
$(ii)$ When a saturated solution is cooled slowly,the solubility of the solute decreases. As a result,the excess solute precipitates out of the solution,often forming crystals of the pure compound.

(N/A) The particles of a colloidal solution are very small,so they cannot be seen with the naked eye. Therefore,the colloidal solution appears to be homogeneous.
However,these particles are large enough to scatter a beam of visible light,i.e.,they exhibit the $Tyndall$ effect. Because they exhibit this property,which is characteristic of mixtures with distinct phases,the colloidal solution is actually heterogeneous.

(N/A) Tincture of iodine: Solute $=$ Iodine,Solvent $=$ Alcohol.
$(b)$ Soda water: Solute $=$ Carbon dioxide $(CO_2)$,Solvent $=$ Water.
$(c)$ Sugar solution: Solute $=$ Sugar,Solvent $=$ Water.
$(d)$ Polluted air: Solute $=$ Pollutant gases (e.g.,$NO_2, SO_2, CO$),Solvent $=$ Air (mainly Nitrogen and Oxygen).
$(e)$ Dilute hydrochloric acid: Solute $=$ Hydrogen chloride gas $(HCl)$,Solvent $=$ Water.

(N/A) $solution$ is a homogeneous mixture of two or more substances.
$(i)$ Tincture of iodine: Solute is $iodine$ and solvent is $alcohol$.
$(ii)$ Polluted air: Solute is $pollutants$ (like $SO_2$, $NO_2$, dust) and solvent is $air$ (mixture of gases).
$(iii)$ Soda water: Solute is $CO_2$ and solvent is $water$.
$(iv)$ Dilute hydrochloric acid: Solute is $HCl$ and solvent is $water$.

(N/A) mixture consists of two or more substances mixed in any proportion. Because the composition of a mixture is variable,the intermolecular forces and the energy required for phase transitions are not constant. Therefore,a mixture does not have a fixed melting or a fixed boiling point; instead,it melts or boils over a range of temperatures.

(B) The "Tyndall effect" is the phenomenon of scattering of a beam of light by particles in a colloid or a fine suspension.
$1$. Copper sulphate solution, sugar solution, and salt solution are all true solutions, where the solute particles are very small (less than $1 \, nm$ in diameter) and do not scatter light.
$2$. A soap solution is a colloidal solution. In a colloid, the particle size is between $1 \, nm$ and $1000 \, nm$, which is large enough to scatter a beam of light passing through it, thus exhibiting the "Tyndall effect".
Therefore, the correct option is $B$.

(A) saturated solution is one in which no more solute can be dissolved at a given temperature.
When a saturated solution is cooled,the solubility of the solute decreases.
As a result,the solution becomes supersaturated,and the excess solute typically crystallizes out of the solution.

(C) homogeneous mixture is a mixture in which the components are uniformly distributed throughout the mixture.
Soda water,copper sulphate solution,and sodium chloride solution are all examples of homogeneous mixtures (solutions).
However,in the context of standard textbook questions of this type,if multiple options appear correct,we look for the most representative example of a true solution.
Actually,all options $A$,$B$,and $C$ are homogeneous mixtures. Starch solution is a colloid,which is heterogeneous.
Assuming the question implies selecting the most common laboratory example of a true solution,$C$ (Sodium chloride solution) is a classic example. However,since $A$,$B$,and $C$ are all technically homogeneous,this question is often presented with specific options. Given the standard classification,$A$,$B$,and $C$ are all homogeneous. If this is a single-choice question,there might be an error in the provided options as multiple are correct. For the purpose of this format,we identify $C$ as a standard homogeneous solution.

(B) An aqueous solution is a solution in which the solvent is water.
In the given options,sodium chloride $(NaCl)$ dissolved in water forms an aqueous solution because water acts as the solvent.
Sulphur in carbon disulphide,iodine in carbon tetrachloride,and sugar in alcohol are non-aqueous solutions because the solvents used are organic liquids,not water.

(D) Step $1$: Sulphur is soluble in carbon disulphide $(CS_2)$.
Step $2$: When sulphur is dissolved in carbon disulphide, it forms a true solution.
Step $3$: $A$ true solution is a homogeneous mixture where the particle size is less than $1 \ nm$ in diameter.
Step $4$: Because the particles are extremely small, they do not scatter a beam of light passing through the solution.
Step $5$: Therefore, a true solution does not exhibit the Tyndall effect.
Step $6$: Thus, the mixture of sulphur and carbon disulphide is homogeneous and does not show the Tyndall effect.

(A) tincture of iodine is a well-known antiseptic solution.
It is prepared by dissolving $2-7\%$ of iodine in a mixture of alcohol and water.
Therefore, the correct composition is iodine dissolved in alcohol.

(N/A) The qualities possessed by Savy are:
$(i)$ Awareness: She knew the ingredients required for the preparation.
$(ii)$ Keen to work: She took the initiative to prepare the drink.
$(iii)$ Self-independent: She performed the task on her own.
$(b)$ Shikanjwi tastes the same throughout because it forms a homogeneous mixture (a solution). In a solution,the solute particles (sugar and salt) are uniformly distributed throughout the solvent (water),ensuring that every part of the mixture has the same composition and taste.

(N/A) Tincture of iodine is applied to the wound because it acts as an antiseptic or disinfectant,which helps in preventing infection by killing microorganisms.
$(b)$ In tincture of iodine,iodine is the solute and alcohol (ethanol) is the solvent.
$(c)$ The values shown by the maid are: presence of mind,basic medical knowledge,care,and responsibility towards the child.