The Amazing World of Solutes, Solvents, and Solutions

Every sip of a homemade ORS tastes the same, never salty in one sip and sweet in the next. Why?

1. aThe sugar and salt settle at the bottom, so each sip is mostly water.
2. bThe salt dissolves in the water, but the sugar floats on top.
3. cThe sugar and salt are evenly distributed throughout the water.
4. dThe sugar and salt can be seen separately with a magnifying device.

When a solution is formed by mixing two liquids, which liquid is called the solute?

1. aThe liquid present in the larger amount
2. bThe liquid present in the smaller amount
3. cThe liquid that is poured in first
4. dThe liquid that is heavier

The chashni (sugar syrup) of gulab jamun is made by dissolving a large amount of sugar in a small amount of water. In this syrup, which is the solvent?

1. aSugar, because it is present in the larger amount
2. bBoth sugar and water, because they are mixed evenly
3. cNeither, because a solid and a liquid cannot form a solution
4. dWater, the liquid, even though less of it is present

A wooden block measures \(10\ \text{cm} \times 5\ \text{cm} \times 4\ \text{cm}\) and has a mass of 120 g. What is its density?

1. a\(0.6\ \text{g/cm}^{3}\)
2. b\(1.67\ \text{g/cm}^{3}\)
3. c\(2.4\ \text{g/cm}^{3}\)
4. d\(6\ \text{g/cm}^{3}\)

Solution X is made by dissolving 2 spoons of salt in 100 mL of water. Solution Y is made by dissolving 4 spoons of salt in 50 mL of water. Which statement is correct?

1. aX is more concentrated, because it has more water.
2. bY is four times as concentrated as X.
3. cX and Y are equally concentrated.
4. dY is twice as concentrated as X.

Which of the following is NOT a solution?

1. aAir, a mixture of gases
2. bOxygen dissolved in water
3. cChashni, sugar dissolved in water
4. dSawdust mixed in water

Why does the density of a substance generally decrease when it is heated?

1. aIts particles come closer together, so its volume decreases while its mass stays the same.
2. bSome of its particles are lost, so its mass decreases while its volume stays the same.
3. cIts particles move apart, so its volume increases while its mass stays the same.
4. dIts particles gain mass, so its mass increases while its volume stays the same.

In science, density is defined as the:

1. amass present in a unit volume of a substance
2. bspace occupied by an object
3. cforce with which the Earth attracts an object
4. dquantity of matter present in an object

A packet of oil is labelled with a volume of 1 litre but a mass of only 910 g. Given that 1 mL of water has a mass of about 1 g, what does this tell us about the oil?

1. aOil is denser than water, with a density of about 1.1 g/mL.
2. bOil is less dense than water, with a density of 910 g/mL.
3. cOil has the same density as water, because the packet holds 1 litre.
4. dOil is less dense than water, with a density of 0.91 g/mL.

An aluminium block has a mass of 27 g and a volume of \(10\ \text{cm}^{3}\). Taking the density of water as \(1\ \text{g/cm}^{3}\), what is the relative density of aluminium with respect to water?

1. a0.37, with no unit
2. b\(270\ \text{g/cm}^{3}\)
3. c2.7, with no unit
4. d\(0.27\ \text{g/cm}^{3}\)

A measuring cylinder has 5 equal small divisions between its 10 mL and 20 mL marks. What is the smallest volume it can read?

1. a1 mL
2. b2 mL
3. c5 mL
4. d10 mL

A metal piece of mass 135 g and density \(2.7\ \text{g/cm}^{3}\) is tied with a thread and lowered fully into a 100 mL measuring cylinder holding 40 mL of water. Up to which mark will the water rise?

1. a90 mL
2. b42.7 mL
3. c50 mL
4. d175 mL

Assertion (A): A saturated solution of baking soda in water at 20 °C can dissolve more baking soda when it is heated to 50 °C.

Reason (R): For most substances, solubility in water increases with an increase in temperature.

1. aBoth A and R are true, and R is the correct explanation for A
2. bBoth A and R are true, but R is NOT the correct explanation for A
3. cA is true, but R is false
4. dA is false, but R is true

Assertion (A): Ice floats on water.

Reason (R): Water has its highest density at 0 °C, the temperature at which it turns into ice.

1. aBoth A and R are true, and R is the correct explanation for A
2. bBoth A and R are true, but R is NOT the correct explanation for A
3. cA is true, but R is false
4. dA is false, but R is true

Assertion (A): When a cube of modelling clay is flattened into a thin sheet, its density decreases.

Reason (R): The density of a substance is independent of its shape or size.

1. aBoth A and R are true, and R is the correct explanation for A
2. bBoth A and R are true, but R is NOT the correct explanation for A
3. cA is true, but R is false
4. dA is false, but R is true

Assertion (A): When water is heated from 20 °C to 70 °C, its density decreases.

Reason (R): When the pressure on a gas is increased, its particles move closer together and its density increases.

1. aBoth A and R are true, and R is the correct explanation for A
2. bBoth A and R are true, but R is NOT the correct explanation for A
3. cA is true, but R is false
4. dA is false, but R is true

1. I. I. In an unsaturated solution, more solute can be dissolved at that temperature.
2. II. II. A solution that is saturated at one temperature behaves as an unsaturated solution if the temperature is increased.
3. III. III. Dilute and concentrated are relative terms.

Which of the statements above about solutions are correct?

1. aOnly I and II
2. bOnly II and III
3. cOnly I and III
4. dI, II and III

1. I. I. When measuring water in a measuring cylinder, the reading is taken at the mark that coincides with the bottom of the meniscus.
2. II. II. For a coloured liquid, the reading is taken at the mark that coincides with the top of the meniscus.
3. III. III. A 250 mL measuring cylinder usually reads a volume more accurately than a 100 mL measuring cylinder.

Which of the statements above about measuring cylinders are correct?

1. aOnly I
2. bOnly II and III
3. cOnly I and II
4. dI, II and III

1. I. I. Mass is measured in newtons.
2. II. II. Weight is the force by which the Earth attracts an object towards itself.
3. III. III. Most balances, except two-pan balances, actually measure weight, though their scales are marked in mass units.

Which of the statements above about mass and weight are correct?

1. aOnly II and III
2. bOnly II
3. cOnly I and II
4. dI, II and III

1. I. I. In Ningel village of Manipur, salt is made by boiling salt solution drawn from wells until the water evaporates and salt crystals form.
2. II. II. Indian systems of medicine have used oils, ghee and milk, besides water, as solvents for drug formulations.
3. III. III. Asima Chatterjee was the first Indian woman to earn a Doctorate of Science.

Which of the statements above about the uses of solvents and solutions are correct?

1. aOnly II and III
2. bOnly I and II
3. cOnly I and III
4. dI, II and III

Match List I with List II:

1. a(i)-Q, (ii)-S, (iii)-R, (iv)-P
2. b(i)-Q, (ii)-S, (iii)-P, (iv)-R
3. c(i)-S, (ii)-Q, (iii)-R, (iv)-P
4. d(i)-S, (ii)-Q, (iii)-P, (iv)-R

Match each quantity in List I with its SI unit in List II:

1. a(i)-P, (ii)-Q, (iii)-S, (iv)-R
2. b(i)-P, (ii)-S, (iii)-Q, (iv)-R
3. c(i)-R, (ii)-Q, (iii)-S, (iv)-P
4. d(i)-R, (ii)-S, (iii)-Q, (iv)-P

Match each observation in List I with its explanation in List II:

1. a(i)-S, (ii)-R, (iii)-P, (iv)-Q
2. b(i)-R, (ii)-S, (iii)-P, (iv)-Q
3. c(i)-R, (ii)-S, (iii)-Q, (iv)-P
4. d(i)-R, (ii)-P, (iii)-S, (iv)-Q

Meena keeps adding sugar to a glass of water and stirring. After a while, some sugar stays at the bottom however much she stirs. Without adding any more water, how can she get this sugar to dissolve?

1. aPut the glass in the refrigerator to cool it
2. bAdd more sugar so that it dissolves faster
3. cWarm the solution gently while stirring
4. dLet the glass stand still for some time

Rahul's aquarium stands next to a sunny window, and the water in it becomes warm every afternoon. Why could this be harmful for his fish?

1. aWarm water can hold less dissolved oxygen than cold water.
2. bWarm water can hold more dissolved oxygen than cold water.
3. cOxygen cannot dissolve in water at all once the water is warm.
4. dWarm water turns into a non-uniform mixture, so the oxygen sinks.

A laboratory assistant must measure 40 mL of water in one step, as accurately as possible. She has measuring cylinders of 25 mL, 100 mL, 250 mL and 500 mL. Which one should she choose?

1. aThe 25 mL cylinder, because it reads the smallest volume
2. bThe 500 mL cylinder, because it has the largest capacity
3. cThe 250 mL cylinder, because it holds 40 mL with room to spare
4. dThe 100 mL cylinder, because it measures 40 mL in one step and reads to 1 mL

Why did Kavya press the tare button after placing the watch glass on the pan?

1. aSo that the balance would show the weight of the rock in newtons
2. bSo that the balance would show only the mass of the rock, not that of the watch glass
3. cSo that the balance would show the volume of the rock
4. dSo that the balance would show the density of the rock directly

What is the density of Kavya's rock?

1. a\(0.33\ \text{g/cm}^{3}\)
2. b\(0.69\ \text{g/cm}^{3}\)
3. c\(3\ \text{g/cm}^{3}\)
4. d\(0.9\ \text{g/cm}^{3}\)

What can be concluded about Arjun's block of wood?

1. aIts density is \(7.2\ \text{g/cm}^{3}\), more than that of water, so it is expected to sink.
2. bIts density is \(3\ \text{g/cm}^{3}\), the same as the rock, because both have the same volume.
3. cIts density is \(1.67\ \text{g/cm}^{3}\), more than that of water, so it is expected to sink.
4. dIts density is \(0.6\ \text{g/cm}^{3}\), less than that of water, so it is expected to float.

Kavya breaks her rock into two identical halves. What are the mass and the density of each half?

1. a18 g and \(1.5\ \text{g/cm}^{3}\)
2. b36 g and \(6\ \text{g/cm}^{3}\)
3. c18 g and \(3\ \text{g/cm}^{3}\)
4. d18 g and \(6\ \text{g/cm}^{3}\)