Explain the following chemical changes?
a) Browning of fruits.
b) Reaction between vinegar and baking soda.
Answers
enzymes of fruits helps to made reaction between oxygen of air and organic substance of fruits. Thus fruit becomes brown.
b)
Answer:
1. Which of the following is a physical change?
(a) Rusting of iron
(b) Combustion of magnesium ribbon
(c) Burning of candle
(d) Melting of wax
Soln:
The answer is (d) Melting of wax
Explanation:
Rusting of iron, combustion and burning of the candle are chemical changes where produced cannot be converted into reactants.
2. Which of the following is a chemical change?
(a) Twinkling of stars
(b) Cooking of vegetables
(c) Cutting of fruits
(d) Boiling of water
Soln:
The answer is (b) Cooking of vegetables
3. A chemical change may involve –
(a) change in colour only
(b) change in temperature only
(c) evolution of gas only
(d) any or all of the above
Soln:
The answer is (d) any or all of the above
Explanation:
A chemical change may involve a change in colour, temperature, smell or evolution of gas, heat, etc.
4. Which of the following is/are true when milk changes into curd?
Its state is changed from liquid to semi-solid.
It changes colour.
It changes the taste.
The change cannot be reversed. Choose the correct option from below :
(a) (i) and (ii) are correct
(b) (ii) and (iii) are correct
(c) (i), (iii) and (iv) are correct
(d) (i) to (iv) are correct