Chemical Reaction and Equation

Give the ratio in which hydrogen and oxygen are present in water by volume.

• 3:1

• 1:2

• 2:1

• 4:1

What type of chemical reactions take place when electricity is passed through water?

• (a) Displacement

• (b) Combination

• (c) Decomposition

• (d) Double displacement

Select the oxidising agent for the following reaction:
H₂S + I₂ > 2HI + S

• (a) I₂

• (b) H₂S

• (C) HI

• (d) S

Pb + CuCl₂ → PbCl₂ + Cu
The above reaction is an example of:

• (a) combination

• (b) double displacement

• (c) decomposition

• (d) displacement

What is observed when a solution of potassium iodide is added to silver nitrate solution?

• (a) No reaction takes place

• (b) White precipitate of silver iodide is formed

• (c) yellow precipitate of Agl is formed

• (d) Agl is soluble in water

what will you observe after heating copper powder strongly in china dish?

• reddish brown colour

• white colour

• black colour

• grey colour

what type of reaction will take place in this activity

• decomposition

• Displacement

• oxidation

• redcution

what colour change you will observe in this activity?

• grey to white

• white to grey

• colourless to grey

• grey to colourless

what are the observations in this activity?

• fouling smell gas

• deposition of water droplets inner surface of the test tune

• light green colour to reddish brown colour

• All of these

In this activity,which metal is more reactive than other metal?

• Cu

• sulphur

• iron

• both Cu and iron