Free Printable CHEMICAL CHANGES AND REACTIONS

1.

What is the molecular formula of calcium nitrate?

a)

$Ca\left(NO_3\right)_2$

b)

$Ca\left(NO_2\right)_3$

c)

$Ca\left(NO\right)_2$

d)

$Ca\left(NO_3\right)_3$

2.

Reaction of nitrogen and oxygen is an example of _____________ reaction.

a)

exothermic

b)

endothermic

3.

Calcium nitrate is obtained when _______________ reacts with dil. nitric acid.

a)

Calcium oxide

b)

Calcium nitrite

c)

Calcium hydroxide

4.

What will be the colour change when copper nitrate is heated?

a)

Blue to Black

b)

Black to blue

c)

White to yellow

d)

Yellow to white

5.

On heating lead[II] nitrate, it gives ________ +________ = Oxygen.

a)

lead oxide + nitric acid

b)

lead oxide + nitrogen dioxide

c)

lead nitrate + nitric oxide

d)

lead nitrate + nitrogen dioxide

6.

Ammonia gas is evolved when ammonium chloride reacts with (a) .

7.

$Na_2SO_3\ +\ H_2SO_{4\ \left[dil\right]}\ \rightarrow\ _{ }$ _________________________.

a)

$Na_2SO_3\ +\ H_2O\ +\ SO_2$

b)

$Na_2SO_4\ +\ H_2O\ +\ SO_2$

c)

$Na_2SO_3\ +\ 2H_2O\ +\ SO_2$

d)

$2Na_2SO_3\ +\ H_2O\ +\ SO_2$

8.

Which gas is evolved when calcium carbonate reacts with dil. hydrochloric acid?

(a)

9.

When __________ reacts with NaOH, pale blue ppt is formed.

a)

$Cu\left(OH\right)_2$

b)

$CuSO_4$

c)

$Pb\left(NO_3\right)_2$

d)

$PbCl_2$

10.

Lead nitrate and sodium chloride when reacts give (a) coloured ppt.

11.

Direct combination reaction is also known as (a) .

12.

Calcium carbonate $\rightarrow\ _{ }$ Calcium oxide + Carbon dioxide. This is an example of

a)

Displacement reaction

b)

Decomposition reaction

c)

Direct combination reaction

d)

Double decomposition reaction

13.

Magnesium + (a) $\rightarrow$ Magnesium sulphate + Copper.

14.

Another name for the yellow ppt formed when lead nitrate is heated, is (a) .

15.

Which one is an example of double decomposition reaction among the following?

a)

$AB\ \rightarrow\ A\ +B$

b)

$X\ +\ YZ\ \rightarrow\ XZ\ +\ Y$

c)

$M^+N^-\ +\ O^+P^-\ \rightarrow\ M^+P^-\ \ +\ O^+N^-$

d)

$M^+N^-\ +\ O^+P^-\ \rightarrow\ M^+O^+\ \ +\ N^-P^-$

16.

Which compound is formed when carbon dioxide reacts with water?

a)

$H_2CO_3$

b)

$H_2CO_2$

c)

$H_3CO_4$

d)

None of the above

17.

Sulphur dioxide + Water $\rightarrow$ (a) .

18.

$4Na\ +\ O_{2\ }\rightarrow$ ____________.

a)

$4NaO_2$

b)

$4Na_2O$

c)

$2Na_2O$

d)

$2Na_2O_2$

19.

$2Al\ \ +\ 3Cl_2\ \rightarrow\ 2AlCl_3$ . In this reaction, aluminium chloride is a/an ___________ salt.

a)

soluble

b)

insoluble

20.

Which salt among the following is insoluble?

a)

FeS

b)

$FeCl_3$

c)

all of the above

d)

none of the above

21.

Phosphorus + Oxygen $\rightarrow$ (a) .

22.

Sulphuric acid is obtained when 'X' reacts with water. What is the name of the element/compound 'X'?

a)

Sulphur

b)

Sulphur dioxide

c)

Sulphur trioxide

d)

Sulphur tetraoxide

23.

Hydrogen chloride is obtained when moist hydrogen gas combines with chlorine. This reaction takes place in presence of diffused sunlight and not direct sunlight because

a)

direct sunlight is not possible

b)

reaction is explosive in direct sunlight

c)

reaction does not take place in direct sunlight

d)

none of the above

24.

What is the temperature needed to prepare ammonia from nitrogen and hydrogen?

a)

$350^oC\ -\ 400^oC$

b)

$400^oC\ -\ 450^oC$

c)

$450^oC\ -\ 500^oC$

d)

$500^oC\ -\ 550^oC$

25.

Nitrides are used in the preparation of ammonia because

a)

Metal nitrate + warm water $\rightarrow$ metal hydroxide + ammonia

b)

Metal nitride + warm water $\rightarrow$ metal hydroxide + ammonia

c)

Metal nitride + cold water $\rightarrow$ metal hydroxide + ammonia

d)

Metal nitride + water $\rightarrow$ metal hydroxide + ammonia.

26.

Decomposition reactions are chemical reactions in which

a)

A compound decomposes to give two new elements

b)

A compound decomposes to give two new compounds

c)

A compound decomposes to give an element & a compound

d)

All of the above

27.

Potassium nitrate on heating decomposes to (a) and Oxygen.

28.

__________ rarely forms hydroxides.

a)

Ag

b)

Pb

c)

Al

d)

Na

29.

Copper carbonate on thermal decomposition gives (a) and carbon dioxide.

30.

Statement A - Ca to Cu: give Metal oxide

Statement B - K, Na: give Nitrite and Oxygen

Statement C - Hg, Ag, Pt: give Metal.

a)

Statement A and C are correct

b)

Statement A and B are correct

c)

Statement B and C are correct

d)

All of the above are correct

31.

What is the molecular formula of Ammonium dichromate?

a)

$\left(NH_3\right)_2Cr_2O_7$

b)

$\left(NH_4\right)_2Cr_2O_6$

c)

$\left(NH_4\right)_2Cr_2O_7$

d)

$\left(NH_2\right)_4Cr_2O_7$

32.

What is the colour of chromic oxide?

(a)

33.

$2NO_2\ \rightarrow\ N_2O_4$ . This reaction takes place at _______.

a)

$140^oC$

b)

$20^oC$

c)

$30^oC$

d)

$120^oC$

34.

$2AgCl\ \rightarrow\ 2Ag\ +\ Cl_2$ . This reaction occurs in presence of __________.

a)

heat

b)

catalyst

c)

light

d)

pressure

35.

Zinc oxide is reduced to Zinc metal by using reducing agents such as _________.

a)

C

b)

CO

c)

Both of the above

d)

None of the above

36.

A ________ electropositive metal displaces a ________ electropositive metal from its aqueous solution.

a)

less, more

b)

more, less

c)

Both of the above

37.

$2Al$ + $3CuSO_4$ $\rightarrow$ ____________ + $3Cu$ .

a)

$Al_2\left(SO_4\right)_2$

b)

$Al_2\left(SO_4\right)_3$

c)

$2Al_2\left(SO_4\right)_3$

d)

$Al_2\left(SO_3\right)_4$

38.

Double decomposition of two salt solutions is also known as (a) .

39.

____________ + $Na_2CO_3$ $\rightarrow$ ___________ + $ZnCO_3$

a)

$Zn\left(NO_2\right)_3$ , $2NaNO_2$

b)

$Zn\left(NO_3\right)_2$ , $2NaNO_3$

c)

$2Zn\left(NO_3\right)_2$ , $NaNO_3$

40.

Which among the following forms gelatinous white ppt and is soluble in excess of NaOH?

a)

Zinc oxide

b)

Lead [II] hydroxide

c)

Zinc hydroxide

d)

Iron [II] hydroxide

41.

What is the colour of ppt formed from $Fe^{2^+}$ ?

a)

Dirty green

b)

Reddish brown

c)

Chalky white

42.

$Pb\left(OH\right)_{2\ }+\ 2HNO_3\ \ \rightarrow$ _______________________.

a)

$Pb\left(NO_3\right)_2\ +\ H_2O$

b)

$Pb\left(NO_3\right)_2\ +\ 2H_2O$

c)

$2Pb\left(NO_3\right)_2\ +\ 2H_2O$

d)

$Pb\left(NO_2\right)_3\ +\ 2H_2O$

43.

$NH_4OH\ +\ HCl\ \rightarrow\ NH_4Cl\ +\ H_2O$ . This is an example of _____________.

a)

Insoluble base and acid

b)

Soluble base and acid

c)

None of the above

44.

Heartburn due to acidity in the stomach can be relieved by taking an (a) .

45.

__ $NH_3$ + __ $O_2$ $\rightarrow$ $4NO$ + __ $H_2O$ + $\Delta T$ . Balance the equation.

a)

3, 5, 6

b)

4, 5, 6

c)

4, 6, 5

d)

4, 5, 5

46.

$-\Delta T$ indicates an (a) reaction.

47.

$CaCO_3\ \ \rightarrow^{ }\ CaO\ +\ CO_2\ -\ \Delta T$ . Is this reaction true or false?

a)

True

b)

False

48.

Silver salts are kept in dark coloured bottle because

a)

they are volatile.

b)

they react in presence of sunlight.

49.

In which state sodium chloride dissociates into its respective ions on passage of electric current?

a)

Fused

b)

Molten

c)

None of the above

50.

______________ and _____________ reacts vigorously in solution state.

a)

Potassium iodide, mercuric chloride

b)

Iodine, phosphorus

c)

Sodium carbonate, tartaric acid

d)

All of the above

51.

$4NH_3\ +\ 5O_2\ \rightarrow\ 4NO\ +\ 6H_2O$ . This reaction takes place in presence of ________________________.

a)

Pt, $450^oC$

b)

Pt, $800^oC$

c)

$MnO_2,\ 450^oC$

d)

$MnO_2,\ 200^oC$

52.

(a) dissociates into Carbon and Hydrogen in presence of sound energy.

53.

On heating, $2Pb_3O_4$ gives (a) and $O_2$ . [according to balanced equation]

54.

Ammonia is obtained when nitrogen reacts with hydrogen. This reaction takes place at (a) atmospheric pressure.

55.

Potassium iodide & mercuric chloride reacts only on (a) together.

CHEMICAL CHANGES AND REACTIONS

Total questions: 55

Worksheet time: 22mins

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