Chemical Reaction and Equations

A substance which oxidises itself and reduces other is known as

• oxidising agent

• reducing agent

• both of these

• none of these

When hydrogen sulphide gas is passed through a blue solution of copper sulphate, a black precipitate of copper sulphide is obtained and the sulphuric acid so formed remains in the solution. The reaction is an example of

• a combination reaction

• a displacement reaction

• a decomposition reaction

• a double decomposition reaction

What happens when copper rod is dipped in iron sulphate solution?

• Copper displaces iron

• Blue colour of copper sulphate solution is obtained

• No reaction takes place

• Reaction is exothermic

A student added dil. HCl to a test tube containing zinc granules & made following observation/s:

• the zinc surface became dull and black

• a gas evolved which burnt with a pop sound

• the solution remained colourless

• the solution becomes green in colour

A dilute solution of sodium carbonate was added to two test tubes - one containing dil HCl (test tube A) and the other containing dilute NaOH (test tube B). The correct observation was

• a brown coloured gas liberated in test tube A

• a brown coloured gas liberated in test tube B

• a colourless gas liberated in test tube A

• a colourless gas liberated in test tube B

• 3 and 5

• 8 and 6

• 4 and 2

• 7 and 1

• an oxidising agent

• a reducing agent

• a dehydrating agent

• a catalyst

• combination reaction

• double displacement reaction

• decomposition reaction

• displacement reaction

White silver chloride in sunlight turns to

• grey

• yellow

• remain white

• red

When copper powder is heated it gets coated with

• black copper oxide

• yellow copper oxide

• red copper oxide

• None of these