give me practice based questions in science for class 10
Answers
Given below are some very important practical based questions to prepare for CBSE class 10 Science exam:
1. A student adds a spoon full of powdered sodium hydrogen carbonate to a flask containing ethanoic acid. List two main observations that he/she must note in his/her notebook about the reaction that takes place. Also, write chemical equation for the reaction
Answer.
Two main observations during the reaction are:
(i) Brisk effervescence
(ii) Sodium acetate is formed
Chemical equation for the reaction is:
2CH3COOH + Na2CO3 → 2CH3COONa + CO2 + H2O
CBSE Class 10 Science Board Exam: Important Short Answer Type Questions
2. Mention the essential material (chemicals) to prepare soap in the laboratory. Describe in brief the test of determining the nature (acidic/alkaline) of the reaction mixture of saponification reaction.
Answer.
Raw Materials Required For preparation of soap in laboratory are :
Vegetable oil
Sodium Hydroxide
Commom salt
Test to determine the nature of reaction mixture: When a red litmus paper is dipped in the reaction mixture, the paper changes its colour to blue. Hence, the reaction mixture of the saponification reaction is basic in nature.
3. Write two precautions to be taken while identifying different parts of an embryo of a dicot seed.
Answer.
(i) The slide should be properly focused.
(ii) Slide should be observed first under low-power magnification and then under high-power magnification of the compound microscope.