class 10 ncert science 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

which of the following is a physical change?

• formation of curd from milk

• ripening of fruits

• Getting salt from sea water

• Burning of wood

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 dilute HCl to a test tube containing zinc granules and made following observations:

• 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

Zn + H₂SO₄ --------> ZnSO₄ + H₂

Above reaction is -

• decomposition reaction

• single displacement reaction

• combination reaction

• synthesis reaction

The reaction in which two compounds exchange their ions to form two new compounds is -

• a displacement reaction

• a decomposition reaction

• an isomerization reaction

• a double displacement reactions

A redox reaction is one in which-

• both the substance are reducedc

• both the substance are oxidised

• an acid is neutralilsed by the base

• one substance is oxidised while the other is reduced

In the equation, NaOH + HNO₃ ------> NaNO₃ + H₂O nitric acid is acting as-

• An Oxidising agent

• an acid

• a nitrating agent

• a dehydrating agent

White silver chloride in sunlight turns to-

• grey

• yellow

• remain white

• red

Black and white photography uses-

• decomposition of silver chloride

• decomposition of silver bromide

• both

• none of these