Question

MAYOOR SCHOOL, NOIDA
CLASS VII (2020-21)
SCIENCE
LESSON - 5
ACIDS , BASES AND SALTS
(Worksheet)
Q.1 Why does a turmeric stain on white shirt is turned to red when it is washed with
soap?
Q.2 look at the figure which shows solutions taken in test tubes A, B, C and D. what
colour is expected, when a piece of red litmus paper is dropped in each test tube?
Nature of the solutions is given in the table for your help
A
Milk in
water
B
C.
"Baking powder Vinegar in
in water
water
Glucose
in water
Q.3. While playing in a park, a child was stung by a wasp. Some elders suggested
applying paste of baking soda and others lemon juice as remedy. Which remedy do
you think is appropriate and why?
Q.4. A small amount of hydrochloric acid is always produced in the stomach. Is it
useful or harmful for us? If excess of acid is produced in the stomach, what should we
do?
Q.5. Write the effect of china rose petals on acidic and basic solutions.
Q.6. After carrying out the neutralization reaction, the test tube immediately found
to be somewhat hot. Explain.​

Answer 1

1. IT CHANGES TO RED BECAUSE SOAP IS A BASE AND TURMERIC IS A NATURAL INDICATOR.... AND WHEN WE RUB A BASE ON TURMRIC IT CAHNGES RED IN COLOUR.
2. A. IT WILL REMAIN RED ONLY

        B. IT WILL TURN BLUE.

        C. IT WILL REMAIN RED.        

        D. IT WILL BE PURPLE IN COLOUR AS IT IS NUETRAL IN NATURE.

    3. WE SHOULD APPLY LEMON JUICE AS A WASP STINGS BASE INTO        THE BODY.

4. IT IS USEFUL AS IT KILLS BACTERIA IN OUR STOMACH ENTERED IN OUR BODY ALONG WITH FOOD.

IF EXCESS IS PRODUCED WE SHOULD TAKE MILK OF MAGNESIA AS IT IS BASIC.

5. ACIDIC-DARK PINK

BASIC-GREEN

6. THE TEST TUBE WAS HOT BECAUSE IN THE REACTION HEAT WAS ALSO RELEASED.