Revision questions SET.2-CLASS.10-SCIENCE

 

Revision questions SET.2

VSA questions.  (1 Mark) Select the most suitable answer from the given options.

1.       Some fruits like mango, lemon, raw grapes, orange, etc., have a sour taste due to the presence of:

Acetic acid

Citric acid

Lactic acid

Oxalic acid

 

2.       Zinc granules on treating with an acid X, form the zinc sulphate (ZnSO4) salt along with the evolution of a gas Y which burns with a pop sound when brought near to a burning candle. Identify the acid X and gas evolved Y.

X- Sulphuric acid and Y- Oxygen gas

X- Hydrochloric acid and Y- Oxygen gas

X- Sulphuric acid and Y- Hydrogen gas

X- Hydrochloric acid and Y- Hydrogen gas

 

3.       Which of the following would change the colour of pH paper to GREEN?

Lemon juice

Common salt

Vinegar

Sodium hydroxide

 

4.       The figure given below represents the experiment carried out between conc. sulphuric acid and sodium chloride, which react with each other to form HCl gas..    

   Which of the follow

ing phenomena occur, when a small amount of acid is added to water?

i. Ionisation

ii. Neutralisation

iii. Dilution

iv. Salt formation

 

                  (i) and (ii)

(i) and (iii)

(ii) and (iii)

(ii) and (iv)         

 

               

6.       Identify the products of the following reaction:

                             

Calcium hydrogen carbonate and chlorine gas

Calcium chloride and water

Calcium oxide, carbon dioxide and water

Calcium chloride, carbon dioxide and water

 

 

7.        The sodium compound used for removing permanent hardness of water.

Baking soda

Washing soda

Sodium chloride

None of these

 

8.       An ant’s sting can be treated with …………which will neutralise the effect of the chemical injected by the ant’s sting into our skin.

Choose the correct option from the following to be filled in the blank space:

Methanoic acid

formic acid

Baking soda

Caustic soda

 

 

9.       Bleaching powder is used as a disinfectant for water to:

Make water tastier

Remove all the dirt from water

Make water germ-free

Make water clear

 

 

10.   Which among the following represents the chemical formula for ‘Plaster of Paris’?

                          

 

11.    Which of the following will NOT give carbon dioxide on treatment with dilute acids?

Marble

Limestone

Baking soda

Quick lime

 

12.   Copper sulphate crystals when heated strongly, lose their water of crystallization to give anhydrous copper sulphate accompanied by a change in color from:

Blue to green

Blue to white

Blue to sky blue

Blue to grey

 

13.   To protect tooth decay, we are advised to brush our teeth regularly. The nature of toothpaste commonly used is

Acidic

Neutral

Basic

Corrosive

 

 

14.   With the increase in in hydrogen ion concentration the pH value will ------.

Increase

Decrease

Remains constant

Keeps changing

 

15.    Vinegar is used in pickling as it is -----.

is an acid

prevents the growth of microbes

prevents drying of a pickle

increases taste

 

 

16.   The gas liberated at the cathode during Chlor-alkali process is----.

Hydrogen

Oxygen

Nitrogen

Chlorine

 

 

17.    Which of the following statement is or are incorrect?

Our body works well within a narrow pH range of 7.0 to 7.8.

When the pH of rain water is about 5.6, it is called acid rain.

If the soil is too acidic (having low pH), then it is treated with materials like quicklime (calcium oxide) or slaked lime (calcium hydroxide) or chalk (calcium carbonate).

Most of the plants grow best when the pH of the soil is close to 4.

 

18.   Nima is writing some statements but she confused to know whether the statements are correct or not? Would you help her?

Metal carbonates and metal hydrogen carbonates are also considered to be bases.

Sodium hydroxide is a base because it dissolves in water to produce hydroxide ions (alongwith sodium ions).

When the solution of a base is diluted by mixing more water in it, then the concentration of hydroxide ions (OH– ions) per unit volume decreases.

All the above

 

19.   Which of the following salts does not contain water of crystallization?

Blue vitriol

Baking soda

Washing soda

Gypsum

 

20.   Methyl orange is ------.

Pink in acidic medium, yellow in basic medium

Yellow in acidic medium, pink in basic medium

Colourless in acidic medium, pink in basic medium

Pink in acidic medium, colourless in basic medium.

 

21.   Which among the following does not reproduce by spore formation?

Penicillium fungus

Yeast fungus

Mucor fungus

Rhizopus fungus

 

 

22.   The asexual reproduction in the Spirogyra involves

Breaking up of filaments into smaller bits

Division of a cell into many cells

Division of a cell into two cells

Formation of a large number of buds

 

23.   The blueprint of body design is ----.

DNA

RNA

Protein

Carbohydrate

 

24.  Reason for the greater similarities among the offsprings produced by asexual reproduction, is

(i) Asexual reproduction involves only one parent

(ii) Asexual reproduction involves two parents

(iii) Asexual reproduction involves gametes

(iv) Asexual reproduction does not involve gametes

 

(i) and (ii)

(i) and (iii)

(ii) and (iv)

(i) and (iv)

 

 

25.   The process of the division of cell into several cells during reproduction in Plasmodium is termed as

Fragmentation

Budding

Multiple fission

Binary fission

 

 

26.   The number of chromosomes in both parents and offsprings of a particular species remains constant because

Chromosomes get doubled after zygote formation

Chromosomes get doubled after gamete formation

Chromosomes get halved during gamete formation

Chromosomes get halved after gamete formation

 

 

 

27.    An organism capable of reproducing by two asexual reproduction methods one similar to the reproduction in yeast and the other similar to the reproduction in Planaria is

Spirogyra

Hydra

Bryophyllum

Paramecium

 

28.   Identify the unisexual flower.

Hibiscus

Papaya

Mustard

Maize

 

 

 

 

29. Which among the following are not the functions of testes at puberty?

(i) Formation of germ cells

(ii) Secretion of testosterone

(iii) Development of placenta

(iv) Secretion of estrogen

 

(i) and (ii)

(i) and (iii)

(ii) and (iv)

(iii) and (iv)

 

 

30.   An example for vegetative propagation by leaves.

Rose

Bryophyllum

Lemon

Banana

 

31.   After fertilization which part of the flower become the seed.

Ovary.

Ovule

Embryo sac

Stigma

 

 

Descriptive questions.  (3 Marks)

a. Write the balanced chemical equation for the following.

(i) Preparation of bleaching powder

(ii) Heating of baking soda

(iii) Conversion of plaster of Paris to gypsum

Ans.

(i)                  Ca (OH)2 + Cl2 → CaOCl2 + H2O

(ii)                2 NaHCO3 (s) → Na2CO3 (s) + H2O(g) + CO2 (g)

(iii)          Gypsum can change in Plaster of Paris (POP) by heat of 373K

 

 

 

b. Why do HCl, HNO3 etc., show acidic characters in aqueous solutions while solutions of compounds like alcohol and glucose do not show acidic character?

Ans.

Solutions like HCl, HNO3 etc. get ionised in aqueous solutions and due to the presence of H+ ions they show acidic characters. While solutions of compounds like alcohol and glucose do not form any such ions so they do not show acidic characters.

 

c. While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?

Ans.

When acid and water mix, the reaction is highly exothermic, the acid may splash, cause burns and even the bottle/container can break. To avoid this and allow the heat evolved to be absorbed by water slowly, acid is added to water for diluting it.

 

 

d. Which gas is usually liberated when an acid reacts with a metal? Illustrate with an example. How will you test for the presence of this gas?

Ans. When an acid reacts with a metal it liberates hydrogen gas.

            E.g., Zn(s) + 2HCl(aq) → ZnCl₂ (aq) + H₂(g)

To test the presence of H₂ gas, bring a burning splinter near the mouth of the test tube where H₂ gas is released, the match stick bums with a pop sound.

 

 

e. You have been provided with three test tubes, one of them contains distilled water and the other two contain an acidic solution and a basic solution respectively. If you are given only red litmus paper; how will you identify the contents of each test tube?

Ans.

Add few drops of solution from all three test tubes on the red litmus paper separately. The solution which turns red litmus to blue contains basic solution. Use this blue litmus paper to test the solutions in other two test tubes. The solution from the test tube which turns blue litmus paper to red will be the acidic solution and solution of the test tube which do not change either red or blue litmus paper contain water.

 

f. Draw and label the parts of a flower.

Ans.

 

g. What is the importance of DNA copying in reproduction?

Ans.

DNA copying is an important phenomenon of reproduction through which the organisms pass on their characteristics to their offspring. It maintains the characteristics in different generations of the species. It also produces variations which are useful for the survival of species for long time.

 

h. What are the different methods of contraception?

Ans.

Contraception is the method to avoid pregnancy. Various methods of contraception are as follows:

         Physical Barrier Methods: Use of condoms, diaphragms, cervical caps can be used. These prevent the entry of sperms into the female genital tract by acting as a barrier between them.

         Chemical Methods: Oral pills can be used which change the hormonal balance and stop release of egg. Vaginal pills kill the sperms.

         Surgical Methods: This includes vasectomy (sperm duct is removed) in males and tubectomy (removal of small portion of fallopian tube) in females.