Kerala SCERT Class 7 Science Chapter 3 Acids and Alkalis Question Answer Solution Here. Kerala Board Class 7 Students can find Here 3rd Chapter Acids and Alkalis Notes provide by our Teacher. Important Question Answer from Chapter 3 Acids and Alkalis.
- Board- Kerala Board.
- Class – 7.
- Subject – Science Part 1
- Chapter – 3.
- Chapter Name – Acids and Alkalis.
- Topic – Question Answer Solution.
Multiple choice Questions.
(1) In Acid, Blue Litmus paper is changes into
a) Red
b) Blue
c) Both
d) None
(2) In Alkali, Blue Litmus paper is changes into
a) Red
b) Blue
c) Both
d) None
(3) Indicators use in the laboratory are
a) Phenolphthalein
b) Methyl orange
c) Turmeric
d) All the above.
4) The PH value of acid is
a) Bellow 7
b) 7
c) above 7
d) None.
5) The PH value of alkali is
a) Bellow 7
b) 7
c) above 7
d) None.
6) The acids are
a) Vinegar
b) Citric acid
c) Sulphuric acid
d) All the above.
7) The is PH value of Neutral solution is
a) Bellow 7
b) 7
c) above 7
d) None.
8) In Acids, Red litmus papar is changes into
a) Red
b) Blue
c) Both
d) None
9) In Alkali, ,Red Litmus paper is changes into
a) Red
b) Blue
c) Both
d) None
10) In Alkali, Turmeric powder colour changes into
a) Red
b) Yellow
c) Both
d) None.
Questions and Answers
(1) Who discovered Hydrogen?
ANS: Henry Cavendish
2) Ants release which acid?
ANS: Formic Acid
(3) What is Alkalis?
ANS: Substances like lime water which turn red litmus blue are called alkalis. They have a bitter taste and are slimy.
(5) Which gas extinguish fire?
ANS: Carbon dioxide
(6) What is neutralisation?
ANS: When definite amounts of acid and alkali are mixed, their acidic and alkaline natures are lost and salt and water are formed. This is called neutralisation.
(7) What is acidity?
ANS: when enough water is not consumed and unhealthy food habits are followed, the amount of acid increases in the stomach. This is called acidity.
Short Questions and answers.
(1) Write acid substances and acid present in them?
ANS: Acids are given bellow.
Food Substance Acid present
Buttermilk – Lactic acid
Vinegar – Acetic acid
Tamarind – Tartaric acid
Lemon – Citric acid
Apple – Malic acid
(2) Which are the alkali substances?
ANS: the substances are given bellow:
i) Calcium hydroxide (lime water)
ii) Sodium hydroxide solution (caustic soda)
iii) Potassium hydroxide solution (caustic potash)
iv) Ammonium hydroxide solution (liquor ammonia dissolved in water).
(3) What are the uses of acids?
ANS:: the uses are given bellow:
i) Pickles and other food substances.
ii) Food preservation and in soft drinks.
iii) Manufacture of chemical fertilizers, paints, dyes etc.
iv) Automobile battery.
v) Production of ink and leather.
(4) What are the uses of alkalis?
ANS: : the uses are given bellow:
i) Manufacture of soap.
ii) Manufacture of detergents and ceramic materials.
iii) Industrial purposes.
iv) Purification of water.