The burning of matchstick is an example for chemical reaction based on______

(a)

Contact in physical states

(b)

electricity

(c)

light

(d)

catalyst

The pigment responsible for browning of apples is______.

(a)

Hydrated iron (II) oxide

(b)

melanin

(c)

starch

(d)

ozone

Limestone contains ______ mainly.

(a)

Calcium chloride

(b)

calcium carbonate

(c)

calcium nitrate

(d)

calcium sulphate

In Haber’s process of producing ammonia ______ is used as a catalyst.

(a)

Nitrogen

(b)

hydrogen

(c)

iron

(d)

nickel

______ is responsible for Global warming.

(a)

Carbon di oxide

(b)

methane

(c)

chlorofluoro carbons

(d)

all the above

Rusting of iron is a _________ change.

(a)

physical

(b)

chemical

(c)

physical and chemical

(d)

neutral

Decomposition of limestone is an example for chemical reaction based on __________

(a)

contact

(b)

electricity

(c)

light

(d)

heat

The chemical reactions carried out by the passage of electricity is called.

(a)

Rusting

(b)

Thermolysis

(c)

Electrolysis

(d)

Photolysis

Enzymes and yeasts are called

(a)

catalysts

(b)

bio catalysts

(c)

chemical catalysts

(d)

physical catalysts

The brown colour of a cut apple is due to

(a)

rusting

(b)

rancidity

(c)

browning

(d)

fermentation