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?
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.
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.
