Question

31The explosion of fire cracker is a ________________.
(1 Point)
physical change
chemical change
biological change
no change
32When we pass carbon dioxide gas into lime water, then lime water turns __________________.
(1 Point)
blue
green
milky
black
33Galvanisation is a process of depositing a layer of _______________.
(1 Point)
copper on iron
zinc on iron
aluminium on iron
nickel on iron
34The colour of copper sulphate changes to green on reaction with iron due to the formation of ____________________.
(1 Point)
copper oxide
copper-iron sulphate complex
iron sulphate
copper metal
35A candle was taken in a dish and then the dish was heated. Even though the candle did not burn, it changed its state and shape. The change involved is _________________.
(1 Point)
physical change
chemical change
biological change
no change
36Fraction of ship's iron has to be replaced every year because it ____________________.
(1 Point)
becomes essential to replace the parts of ship, which are damaged by rusting
increases the carrying capacity of ship
makes ship heavier
gives new look to the ship
37Identify the type of change in the given picture:
(1 Point)
physical change
chemical change
biological change
no change
38Renu observed that the key of her bicycle has acquired a film of brownish substance. The reason behind the change is _______________.
(1 Point)
rusting
galvanisation
crystallization
evaporation
39The formula of magnesium hydroxide is ________.
(1 Point)
MgO
MgO₂
MgO₃
Mg(OH)₂
40​

Answer 1

Answer:

I don't no.............................