Chemistry NTSE Stage-1

NTSE STAGE-I DAILY PRACTICE PROBLEMS SESSION-2012-13 CHEMISTRY

DPP : 01

Class –X

TOPIC : STRUCTURE OF ATOM & ACIDS BASES AND SALTS 1.

2.

3.

Aqua regia consists of HCl and HNO3 in the ratio: (A) 3 part HCl + 1 part HNO3

(B) 1 part HCl + 3 part HNO3

(C) 3 part HCl + 1 part HNO2

(D) 3 part HCl + 1 part H2SO4

Which is the correct order of the acidic strength ? (A) HClO4 > HClO3 > HClO2

(B) H3PO4 > H3PO3 > H3PO2

(C) HF > HCl > HBr

(D) H2S > HF > HCl

Acids are the substance that yield H+ ions in aqueous solutions while bases yield OH– ions. In a neutral solution : (A) There are no H+ ions (B) There are no OH– ions (C) There are neither H+ nor OH– ions (D) H+ and OH– ions are present in very small but equal number

4.

In which of the following cases the acidic strength is highest ? (A) pka = 5

5.

6.

(2) CO2

(3) SO3

(4) PH3

(A) (1) and (2)

(B) (2) and (3)

(C) (3) and (4)

(D) (2) and (4)

(C) 2, 8, 3

(D) 2, 8, 5

Electronic configuration of Si in ground state is (B) 2, 8, 4

Which of the following has maximum number of electrons ? (C) O

9.

(D) All have same no of electrons

(A) configuration of non-metals

(B) configuration of metals

(C) configuration of inert gases

(D) None of these

Which of the following pairs are isobars ? 235 239 92 U , 94 Pu

(B)

83 36 Kr

,

84 36 Kr

(C)

19 10 Ne

,

19 9 F

(D)

139 58 Ce

,

140 58 Ce

Which of the following metals represent variable valency ? (A) Cr

11.

(B) Ne

2–

Electronic configurations of ions are like -

(A) 10.

(D) pka = 3

(1) CO,

(A) N 3 –

8.

(C) pka = 6

Which of the following gases on dissolution in water make the solution acidic ?

(A) 2, 8, 2 7.

(B) pka = 4

(B) Sn

(C) Fe

(D) All

1 mole of a diatomic element X2 contains 34 and 40 moles of electrons and neutrons respectively. The formula of the element is (A)

74 34

X

(B)

37 17

X

(C)

40 34

X

(D)

40 20

X

12.

13.

Among the following groups which represents the collection of isoelectronic species ? (A) NO+ , C 22 – , O2–, CO

(B) N2 , C 22 – , CO, NO

(C) CO , NO+, CN–, C 22 –

(D) NO, CN–, N2, O2–

Anhydrite is (A) CaSO4.2H2O

14.

(C) both

(D) None of these

(B) Na2CO3.10H2O

(C) NaHCO3

(D) CaOCl2

(B) oil of vitriol

(C) blue vitriol

(D) white vitriol

Salt used in the manufacturing of chloroform is -

FeSO4. 7H2O is (A) green vitriol

17.

(D) CaO

(B) reduction

(A) NaCl 16.

(C) CaSO4

Bleaching powder sterilizes drinking water by (A) oxidation

15.

(B) CaSO4. 1/2H2O

10 5B

and

11 5B

are two isotopes of boron. If average mass number of boron is 10.2, what is the percentage of

each isotope ? 18.

For an atom having atomic number Z and mass number A, the total number of neutrons inside the nucleus is 16. Also the atomic number and mass number satisfy the relation : A + Z = 46. Calculate the total number of nucleons in the atom.

19.

Match the following Column I (i) Cathode rays (ii) Dumb-bell (iii) Alpha particles (iv) Moseley (v) Heisenberg (vi) X-rays

20.

Column-II (a) Helium nuclei (b) Uncertainty principle (c) Electromagnetic radiation (d) p-orbital (e) Atomic number (f) Electrons

(a) Name an element whose nucleus does not contain any neutrons. (b) Hydrogen has three isotopes written as :

1 2 3 1H , 1 H , 1 H

Explain why these isotopes have almost identical chemical properties.

NTSE STAGE-I DAILY PRACTICE PROBLEMS SESSION-2012-13 CHEMISTRY

DPP : 02

Class –X

TOPIC : PERIODIC TABLE 1.

The electronic configurations for some neutral atoms are given below (1) 1s2, 2s2, 2p6,3s2 (2) 1s2, 2s2, 2p6, 3s1 (3) 1s2, 2s2 2p6, 3s2 3p2 (4) 1s2, 2s2, 2p6, 3s2, 3p3 Which of these is expected to have the highest second ionisation enthalpy ? (A) 1 (B) 2 (C) 3 (D) 4

2.

If each orbital can take maximum of three electrons, the number of elements in the third period of the periodic table will be : (A) 12 (B) 5 (C) 8 (D) 24

3.

Which gas is filled in hot air balloons ? (A) Nitrogen (B) Helium

(C) Oxygen

(D) Chlorine

4.

Which of the following statements is not true for noble gases ? (A) They have stable configuration. (B) All of them contain eight electrons in their outermost shell except helium. (C) They are the zero group elements. (D) They are coloured.

5.

An element with atomic number 17 is (A) a rare gas. (B) a halogen gas.

(C) an alkali metal.

The noble gases among the following are (A) hydrogen, nitrogen and oxygen. (C) helium, neon and argon.

(B) fluorine, chlorine and bromine. (D) sodium, potassium and calcium.

6.

(D) a transition metal.

7.

Which of the following pairs of elements does not belong to same group ? (A) Cl, Br (B) N, P (C) Mg, Ca (D) Al, Si

8.

Locate each of the following elements on the periodic table. p. Most electronegative element q. Group IVA element with the largest atomic radius r. Group VIA element with the smallest atomic radius s. Group IIIA element that is a semiconductor t. Group VA element that forms the strongest -bonds

(A)

sq t

p

(B)

q

r

(C)

p

r sq

t

t r p

s

(D)

qt p

s

r

9.

The atom having smallest size in the list below is Na, Si, Cl, Ar (A) Na

10.

(B) Cl

(B) Ne

(B) F– < O2– < N3–

(C) Na < Li < K

(D) Fe3+ < Fe2+ < Fe4+

(B) greater

(C) smaller

(D) half

In a period, the ionisation energy is lowest for the : (A) noble gases

14.

(D) all have equal size

Compared to the second ionisation energy (IE2) of an atom, the third ionisation energy (IE3) is : (A) the same

13.

(C) Mg+2

The correct order of atomic radii is (A) Na < Be < B

12.

(D) Al

Which of the following is the smallest in size ?

(A) Na+ 11.

(C) Si

(B) halogens

(C) alkaline

(D) alkali metals

The first (IE1) and second (IE2) ionisation energies (kJ mol–1) of a few elements are shown below : IE1

IE2

(a)

2372

5251

(b)

520

7300

(c)

900

1760

(d)

1680

3380

Which of the element is likely to be a non-metal ? (A) (a)

(B) (b)

(C) (c)

(D) (d)

15.

With reference to periodic table, indicate (a) An element that is in group III A and 3rd period. (b) Second transition element of fourth period. (c) The group which accommodates lanthanides and actinides. (d) The element of 15th group which has metallic as well as non- metallic behaviour.

16.

Match List-I with List - II : List - I (a) (P+1) > N (b) (P+1) = 7 (c) (P+1) < N (d) (P+1) = N Here, P = Number of period. N = Number of valence electrons.

17.

List - II (p) Al (q) Pb (r) C (s) Si

Match the column-I with column II and Column III. Column-I Column-II (Atomic number) (Group) (a) 13 (p) III A (b) 35 (q) VIIA (c) 56 (r) II A (d) 78 (s) VIII

Column-III (Period) (u) 6 (v) 5 (w) 3 (x) 4

NTSE STAGE-I DAILY PRACTICE PROBLEMS SESSION-2012-13 CHEMISTRY

DPP : 03

Class –X

TOPIC : ATOMS AND MOLECULES AND NATURE OF MATTER 1.

2.

3.

Which of the following is not a compound ? (A) Marble (B) Washing soda

(C) Quick lime

(D) Brass

Which of the following is an example of homogeneous mixture ? (A) Brass (B) Muddy water (C) Soil

(D) All

Which of the following is a compound ? (A) Stainless steel (B) Brass

(D) Iodine

(C) Iron sulphide

4.

A sample of air is found to have 0.03% carbon dioxide and another sample 0.02%. This illustrates that(A) air is a compound. (B) air is an element. (C) air does not follow the law of constant proportions. (D) air is a mixture.

5.

Soda water is an example of (A) gas in a liquid mixture (C) solid in a solid mixture

6.

(B) liquid in a gas mixture (D) solid in a gas mixture

The smell of perfume spreads out by a process known as (A) evaporation (B) diffusion (C) condensation

(D) fusion

7.

Which of the following processes is used to obtain pure water from a common salt solution ? (A) Filtration (B) Distillation (C) Fractional distillation (D) None of these

8.

Which of the following mixtures can be separated by fractional distillation ? (A) Acetone and ethyl alcohol (B) Chloroform and ethyl alcohol (C) Ethyl alcohol and water (D) All of these

9.

The substance which is left in the vessel after the fractional distillation of petroleum is(A) petrol (B) vaseline (C) coaltar (D) diesel

10.

Purity of organic liquid can be checked by its characteristic (A) boiling point (B) volume (C) solubility in water

(D) solubility in alcohol

11.

The process of obtaining pure crystals of copper sulphate from copper sulphate solution is known as (A) crystallisation (B) galvanisation (C) rusting (D) None of these

12.

Match List-I (mixtures) with List-II (separation methods) and choose the correct answer using the codes given below the lists : List-I List-II (a) NaCl in water 1. Chromatography (b) I2 in water 2. Distillation (c) Red ink and blue ink 3. Solvent extraction (d) NH4Cl and NaCl 4. Sublimation Codes : a b c d a b c d (A) 2 3 1 4 (B) 3 2 1 4 (C) 2 3 4 1 (D) 3 2 4 1

13.

We can get a pure liquid from a solution by (A) distillation

14.

(B) crystallization

(D) sedimentation

Which of the following sample contains the maximum number of atoms ? (A) 1 mg of C4H10

15.

(C) evaporation

(B) 1 mg of N2

(C) 1 mg of Na

(D) 1 ml of water

X and Y are two element which form X2Y3 and X3Y4 . If 0.20 mol of X2Y3 weighs 32.0 g and 0.4 mol of X3Y4 weighs 92.8 g, the atomic weights of X and Y are respectively. (A) 16.0 and 56.0

16.

(B) 8.0 and 28.0

(C) 56.0 and 16.0

(D) 28.0 and 8.0

Complete the following table —

S.No. Substance 1

PH3

2

HCl

3

CH4

4

H2S

5

HOCl

Molecula r Tota l no. of Mass of Subs. No. of Moles No. of atoms Mass molecules 17 g 3 mole 1.5 × 1023 68 g 0.5 mole

17.

Calculate the total number of electrons in 16 g of methane.

18.

From 160 g of SO2(g) sample, 1.2046 × 1024 molecules of SO2 are removed then find out the volume of left over SO2(g) at STP.

19.

14 g of nitrogen gas and 22 g of CO2 gas are mixed together. Find the volume of gaseous mixture at STP.

20.

Show that in the reaction N2(g) + 3H2(g)  2NH3(g), mass is conserved.

CHEMISTRY _NTSE STAGE-I DPP-1 Ques 1 Ans A Ques 11 Ans B

17. 20 %

2 A 12 C

3 D 13 C

4 D 14 A

5 B 15 D

6 B 16 A

7 D

8 C

9 C

10 D

18. 31 19.

CHEMISTRY _NTSE STAGE-I DPP-2

Ques 1 Ans B Ques 11 Ans B

2 A 12 B

3 B 13 D

4 D 14 A

5 B

6 C

7 D

8 B

9 B

10 C

CHEMISTRY _NTSE STAGE-I DPP-3

Ques 1 Ans D Ques 11 Ans A

17. NA

18. 11.2 litre

2 A 12 A

3 C 13 A

4 D 14 D

5 A 15 C

19. 1 × 22.4 litre

6 B

7 B

8 D

20. 34 g

9 B

10 A