The Amazing World of Solutes, Solvents, and Solutions
Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.
Types of Solutions and Solubility
SubtopicTypes of Solutions and Solubility under The Amazing World of Solutes, Solvents, and Solutions for Grade 7 CBSE.
Preview questions (no answers)
- 1.
In a solution, the particles of the solute are so small that they:
A.Can be seen with a magnifying glass
B.Settle down after some time
C.Cannot be seen even with a microscope
D.Turn the solution opaque
- 2.
Which of the following will NOT dissolve in water?
A.Glucose
B.Washing soda
C.Mustard oil
D.Potassium permanganate
- 3.
When you open a bottle of soda, bubbles come out. This shows that the gas was ______ in the liquid.
A.Melted
B.Frozen
C.Dissolved
D.Boiled
- 4.
The 'strength' or 'thickness' of a solution based on the amount of solute is often referred to as its:
A.Weight
B.Solubility
C.Concentration
D.Volume
- 5.
If a solution contains of alcohol and of water, which one is generally referred to as the solvent in common laboratory practice?
A.Alcohol
B.Water
C.Neither
D.The one added first
- 6.
A student finds that of a substance dissolves in of water at . If she tries to dissolve of the same substance in of water at , the extra will:
A.Dissolve slowly
B.Stay undissolved at the bottom
C.Make the water evaporate
D.Turn into a gas
- 7.
Which of the following will result in the fastest dissolution of a salt cube in water?
A.Placing the cube in ice-cold water
B.Placing the cube in still water at room temperature
C.Crushing the cube and stirring it in hot water
D.Crushing the cube and leaving it in cold water without stirring
- 8.
A student prepares a saturated solution by dissolving a salt in of water at . The solubility of this salt is per of water at and per of water at . The student then performs the experiment as shown in the flowchart below. What is the total mass of the crystals formed at the end of the procedure?
A.B.C.D. - 9.
If the solubility of a certain substance is 'infinite' in water (like Alcohol), what does this mean?
A.No amount of the substance can ever be dissolved.
B.The substance and water are miscible in all proportions and never form a saturated solution.
C.The substance can only dissolve if the water is boiling.
D.The substance is a solid that dissolves instantly.
- 10.
What happens to the boiling point of water when a non-volatile solute like salt is dissolved in it?
A.The boiling point decreases.
B.The boiling point remains the same.
C.The boiling point increases.
D.The water will not boil at all; it will only evaporate.
Download the worksheet for The Amazing World of Solutes, Solvents, and Solutions - Types of Solutions and Solubility to practice offline. It includes additional chapter-level practice questions.
Saturated and Unsaturated Solutions
SubtopicSaturated and Unsaturated Solutions under The Amazing World of Solutes, Solvents, and Solutions for Grade 7 CBSE.
Preview questions (no answers)
- 1.
Why does powder dissolve faster than a large crystal?
A.Powder is heavier
B.Powder has more surface area in contact with the solvent
C.Crystals are colder
D.Powder is more colorful
- 2.
If you have a saturated solution, what is the state of balance between dissolving and crystallizing called?
A.Unsaturation
B.Equilibrium
C.Dilution
D.Evaporation
- 3.
Which of these is a characteristic of a solution?
A.The parts can be seen clearly
B.The parts separate on standing
C.It is a homogeneous mixture
D.It is always blue
- 4.
Can we define solubility without mentioning temperature?
A.Yes, temperature does not matter
B.No, solubility changes with temperature
C.Only for liquids
D.Only for gases
- 5.
When you open a bottle of a carbonated drink, bubbles of gas escape. This happens because:
A.The solvent is boiling.
B.The solubility of the gas decreases as the pressure is released.
C.The gas is reacting with the air.
D.The liquid is turning into a solid.
- 6.
What is the usual state of a solution formed by dissolving iodine in alcohol?
A.Solid
B.Liquid
C.Gas
D.Plasma
- 7.
Which of the following describes a 'binary solution'?
A.A solution with two solvents.
B.A solution with two solutes and one solvent.
C.A solution made of only two components: one solute and one solvent.
D.A solution that can only exist at two different temperatures.
- 8.
What is the primary reason why fish find it difficult to survive in warm water compared to cold water, in terms of solution chemistry?
A.Warm water is always saturated with salt.
B.The solubility of oxygen (gas) decreases as the water temperature increases, making the water 'less saturated' with oxygen for breathing.
C.Warm water dissolves the scales of the fish.
D.The fish's metabolism requires more sugar which doesn't dissolve in warm water.
- 9.
If you add of a solute to of water and it forms an unsaturated solution, and the solubility is per water, how much more solute is needed to make it saturated?
A.10 g
B.20 g
C.5 g
D.15 g
- 10.
Why is the solubility of solids usually expressed as 'mass of solute per of solvent' rather than 'mass of solute per of solution'?
A.Because the mass of the solvent is easier to measure.
B.Because the mass of the solvent remains constant while the mass of the solution changes as solute is added.
C.Because the solution mass includes the solute which is what we are trying to measure.
D.It is a convention and both are actually the same.
Download the worksheet for The Amazing World of Solutes, Solvents, and Solutions - Saturated and Unsaturated Solutions to practice offline. It includes additional chapter-level practice questions.
Acids, Bases, and Natural Indicators
SubtopicAcids, Bases, and Natural Indicators under The Amazing World of Solutes, Solvents, and Solutions for Grade 7 CBSE.
Preview questions (no answers)
- 1.
Which of these is a liquid solution of a solid in a liquid?
A.Air
B.Sea water
C.Oxygen gas
D.Brass
- 2.
What is the taste of a basic substance like baking soda?
A.Sour
B.Bitter
C.Sweet
D.No taste
- 3.
Which of the following contains tartaric acid?
A.Unripe mangoes
B.Curd
C.Vinegar
D.Spinach
- 4.
Which indicator turns green when added to a window cleaner solution?
A.Litmus
B.China rose
C.Turmeric
D.Methyl orange
- 5.
A student performs an experiment testing dry baking soda with red litmus paper under two different conditions. Based on the observations shown in the flowchart, what is the most accurate conclusion about how indicators detect the nature of a substance?
A.Baking soda is a neutral substance that only reacts with moisture to create a new acidic compound.
B.Most substances show their acidic or basic properties only when they are in a solution form or in the presence of water.
C.Red litmus paper is specifically designed to only detect liquid chemicals and cannot react with any solid powders.
D.Dry baking soda is naturally more acidic than moist baking soda, which prevents the litmus paper from changing color.
- 6.
Which property of a base makes it useful in cleaning greasy surfaces?
A.Its sour taste
B.Its ability to turn blue litmus red
C.Its slippery/soapy feel
D.Its ability to release oxygen
- 7.
Baking soda is chemically known as:
A.Sodium chloride
B.Sodium hydroxide
C.Sodium hydrogen carbonate
D.Calcium carbonate
- 8.
A student is investigating the chemical properties of two unknown solutions, X and Y. Based on the experimental observations recorded in the flowchart below, which of the following pairs correctly identifies the most likely substances for X and Y?
A.X: Lemon Juice; Y: Milk of Magnesia
B.X: Window Cleaner; Y: Dilute Sulfuric Acid
C.X: Distilled Water; Y: Vinegar
D.X: Baking Soda Solution; Y: Soap Solution
- 9.
An organic substance found in grapes and unripe mangoes is used to give a tangy taste to food. This substance is:
A.Oxalic acid
B.Tartaric acid
C.Lactic acid
D.Acetic acid
- 10.
A substance 'P' is found in the laboratory. It turns blue litmus red and reacts with baking soda to release a gas that turns lime water milky. What is 'P'?
A.Sodium hydroxide
B.Distilled water
C.Dilute Hydrochloric acid
D.Calcium hydroxide
Download the worksheet for The Amazing World of Solutes, Solvents, and Solutions - Acids, Bases, and Natural Indicators to practice offline. It includes additional chapter-level practice questions.
Neutralisation in Everyday Life
SubtopicNeutralisation in Everyday Life under The Amazing World of Solutes, Solvents, and Solutions for Grade 7 CBSE.
Preview questions (no answers)
- 1.
The presence of which ion makes a substance acidic?
A.Hydroxyl ions
B.Hydrogen ions
C.Chloride ions
D.Sodium ions
- 2.
Which of these is NOT a base?
A.Magnesium hydroxide
B.Sodium hydroxide
C.Acetic acid
D.Calcium hydroxide
- 3.
If we mix an equal amount of a strong acid and a strong base, the resulting solution will be:
A.Very acidic
B.Very basic
C.Neutral
D.Bitter
- 4.
What is the chemical formula for water, a product of neutralisation?
A.B.C.D. - 5.
What is the nature of the solution formed when equal amounts of a strong acid and an equally strong base are mixed?
A.Highly acidic
B.Highly basic
C.Neutral
D.Moderately acidic
- 6.
Which of the following is a consequence of failing to neutralise acidic soil?
A.Plants may not be able to absorb nutrients effectively
B.Plants will grow much faster
C.The soil will turn into sand
D.The soil will become extremely basic over time
- 7.
Why does the temperature of the test tube rise during the reaction between sulphuric acid and potassium hydroxide?
A.Energy is required to break the bonds
B.Heat is released during the formation of salt and water
C.The base is boiling
D.The acid is evaporating
- 8.
In the context of the CBSE curriculum for Grade 7, 'neutralisation' in everyday life is best described as a reaction between:
A.Two different salts
B.An acid and a base to form salt and water
C.A solute and a solvent to form a saturated solution
D.A metal and a non-metal
- 9.
Why is it important to treat factory waste before discharge, even if the waste is only 'mildly' acidic?
A.The cumulative effect in a large water body can still significantly drop the pH, harming the ecosystem
B.Mildly acidic waste turns into a strong base over time
C.Acidic waste causes the water to freeze at higher temperatures
D.It is not important; only strong acids are dangerous
- 10.
Magnesium Hydroxide is called 'Milk of Magnesia' because:
A.It is extracted from cow's milk
B.Its white, milk-like appearance as a suspension in water
C.It contains high amounts of calcium
D.It tastes like milk
Download the worksheet for The Amazing World of Solutes, Solvents, and Solutions - Neutralisation in Everyday Life to practice offline. It includes additional chapter-level practice questions.
Physical and Chemical Changes
SubtopicPhysical and Chemical Changes under The Amazing World of Solutes, Solvents, and Solutions for Grade 7 CBSE.
Preview questions (no answers)
- 1.
Beating a piece of aluminum to make aluminum foil is a:
A.Physical change
B.Chemical change
C.Natural change
D.Chemical reaction
- 2.
The melting of a glacier due to global warming is a:
A.Chemical change
B.Physical change
C.Periodic change
D.Biological change
- 3.
During a chemical change, which of the following might occur?
A.Evolution of a gas
B.Change in color
C.Production of heat
D.All of the above
- 4.
Which of the following can be categorized as a reversible physical change?
A.Burning of incense sticks
B.Melting of ice cream
C.Cooking an egg
D.Bursting a cracker
- 5.
A student dissolves a spoonful of salt in a glass of water. Which of the following statements is true about this process?
A.It is a chemical change as salt disappears
B.It is a physical change as salt can be recovered by evaporation
C.It is a chemical change because a new liquid is formed
D.It is an irreversible physical change
- 6.
Which of the following is a chemical change that happens inside our body?
A.Chewing of food
B.Digestion of food
C.Movement of muscles
D.Circulation of blood
- 7.
During the process of crystallization, the solution must be:
A.Dilute
B.Super-saturated or hot saturated
C.Very cold
D.Unsaturated
- 8.
Sublimation of Ammonium Chloride involves the change of state from solid directly to gas. Why is this classified as a physical change despite the high heat required?
A.Because the chemical composition of Ammonium Chloride remains unchanged.
B.Because the gas produced can be cooled back into the original solid.
C.Both A and B are correct.
D.Because it is an endothermic reaction.
- 9.
When we dissolve an effervescent tablet in water, bubbles are produced and the tablet disappears. What type of change is this?
A.Only physical because the tablet dissolves in water.
B.Only chemical because bubbles of a new gas are produced.
C.Both physical and chemical changes are occurring simultaneously.
D.Neither, it is a biological change.
- 10.
A student wants to prove that air and moisture are both necessary for rusting. Which setup would best demonstrate this?
A.An iron nail in a tube with dry air and anhydrous calcium chloride.
B.An iron nail completely submerged in boiled distilled water with a layer of oil on top.
C.An iron nail halfway submerged in ordinary tap water in an open tube.
D.An iron nail in a vacuum chamber with a beaker of water.
Download the worksheet for The Amazing World of Solutes, Solvents, and Solutions - Physical and Chemical Changes to practice offline. It includes additional chapter-level practice questions.
Rusting of Iron and Crystallisation
SubtopicRusting of Iron and Crystallisation under The Amazing World of Solutes, Solvents, and Solutions for Grade 7 CBSE.
Preview questions (no answers)
- 1.
If you leave an iron nail in a glass of distilled water and another in a glass of salty water, which nail will rust more?
A.The one in distilled water
B.The one in salty water
C.Both will rust equally
D.Neither will rust
- 2.
Which of these is a solution where the solvent is NOT water?
A.Saltwater
B.Sugar syrup
C.Iodine in alcohol
D.Lemonade
- 3.
Pure crystals of which substance can be obtained using dilute sulphuric acid and boiling water?
A.Iron oxide
B.Common salt
C.Copper sulphate
D.Calcium carbonate
- 4.
Which of the following is a way to speed up the process of making a solution?
A.Cooling the solvent
B.Using large chunks of solute
C.Heating the solvent
D.Keeping the solution still
- 5.
In the experiment to obtain copper sulphate crystals, what indicates that the solution has reached the 'crystallisation point'?
A.The solution starts boiling rapidly
B.Small crystals start appearing on a glass rod dipped in the solution
C.The color of the solution turns from blue to colorless
D.The solution becomes completely solid instantly
- 6.
To prevent rust, iron is sometimes coated with Chromium. This process is called:
A.Galvanization
B.Chrome plating
C.Anodizing
D.Alloying
- 7.
Which of the following is NOT a characteristic of a crystal?
A.Definite geometric shape
B.Highly ordered internal structure
C.Purity of the substance
D.Variable chemical composition throughout
- 8.
A piece of iron is painted to prevent rusting. After 2 years, the paint begins to peel. What is the most common reason for the paint to start peeling from the inside out?
A.The paint itself has turned into rust
B.A small crack allowed moisture to enter, and the resulting rust volume expansion pushed the paint off
C.The iron atoms moved through the paint into the air
D.The paint reacted with the sunlight to become a liquid
- 9.
When a saturated solution of salt is cooled, the excess solute comes out of the solution. This is because:
A.The kinetic energy of the solvent molecules increases
B.The solubility of most solids decreases with a decrease in temperature
C.The salt reacts with the cold air to become a solid
D.The volume of the solvent increases when it gets cold
- 10.
In the process of alloying to make stainless steel, why is 'Carbon' added along with Chromium and Nickel?
A.To give the steel a black color
B.To increase the hardness and strength of the iron
C.To make the steel more soluble in water
D.To prevent the steel from conducting electricity
Download the worksheet for The Amazing World of Solutes, Solvents, and Solutions - Rusting of Iron and Crystallisation to practice offline. It includes additional chapter-level practice questions.