NEET TEST SERIES 148 CHEMISTRY

1. A mixture of gases contains and O₂ gases in the ratio of 1:4 (w/w). What is the molar ratio of the two gases in the mixture?

(a) 16:1
(b) 2:1
(c) 1:4
(d) 4:1

2. In H-atom spectrum electron jumps from 5th excited state to 1^st excited state then total number of spectral lines, number of lines in Lyman series and Paschen series respectively are:

(a) 10,4,3
(b) 15, 0,4
(c) 15, 4,5
(d) 10,0,3

3. The angular momentum of electron in ‘d’ orbital is equal to:

(a) 2√3 h
(b) h
(c) √(6h)
(d) √2h

4. Which of the following is correct with respect to -l effect of the substituents? [R- alkyl]

(a)-NH₂>-OR >-F
(b) -NR₂<-OR <-F
(c) -NH₂<-OR <-F
(d) -NR₂>-OR > -F

5. The species, having bond angles of 120 is:

(a) PH₃
(b) CIF₃
(c) NCI₃
(d) BCI₃

6. The species Ar, K⁺and Ca²⁺ contain the same number of electrons. In which order do their radii increase?

(a)  Ca²⁺< K⁺ < Ar
(b)  K⁺ < Ar <Ca²⁺
(c) Ar < K ⁺<Ca²⁺
(d) Ca²⁺< Ar <K ⁺

7. The solubility of BaSO₄ in water is 42 ×10^-3 gL^– at 298K. The value of solubility product K_sp) will be [Given molar mass of BaSO_4= 233 g mol^– ]

(a) 1.08 ×10 ^-10  mol² L^-2
(b) 1.08 ×10 ^-12  mol² L^-2
(c) 1.08 ×10 ^-14  mol² L^-2
(d) 1.08 ×10 ^-8  mol² L^-2

8. What is the activation energy for a reaction if its rate doubles when the temperature is raised from 20°C to 35°C? (R = 8.314 J mol^-1  K^-1)

(a) 342 kj mol_–¹
(b) 269 kJ mol^-1
(c) 34.7 kJ mol^-1
(d) 15.1 kJ mol^-1

9. In which of the following options the order of arrangement does not agree with the variation of property indicated against it?

a) 1 < Br < Cl < F (increasing electron gain enthalpy)
b) Li <Na <K <Rb (increasing metallic radius)
c) Al³⁺<Mg²⁺< Na⁺ < F^– (increasing ionic size)
d) B<C<N<O (increasing first ionization enthalpy)

10. Aqueous solution of which of the following compounds is the best conductor of electric current?

(a) Hydrochloric acid, HCI
(b) Ammonia, NH₃
(c) Fructose, C₂ H₂ O₂
(d) Acetic acid, C₂ H₂ O₂

11. The rate of first-order reaction is 0.04 L^-1 s^-1 at 10 seconds and 0.03 mol L^-1 s^-1 at 20 seconds after initiation of the reaction. The half-life period of the reaction is:

(a) 44.1 s
(b) 54.1 s
(c) 24.1 s  
(d) 34.1 s

12. In acidic medium, H₂O₂, changes Cr₂O₇^2-, to CrO₅ which (-O-O-) bonds. Oxidation state of Cr in CrO₅ has two (0-0)1 is:

(a) +5
(b) + 3
(c) + 6
(d) -10

13. The reaction of H₂O, with hydrogen sulphide is an example of …………. reaction:

(a) addition
(b) oxidation
(c) reductio
(d) redox acidic

14. The enthalpy of vaporization of H₂O(1) is x kJ/mol and enthalpy of formation of water vapour y kJ/mol. Enthalpy of formation of H₂O(I), would be

(a) (y – x) kj mol^-1
(b) (x – y)kj mol^-1
(c) (x + y) kJ  mol^-1
(d) (2x – y) kj  mol^-1

15. Equal four acid 1, 2, 3 and 4 are mixed in a container. The concentration of hydrogen ion in the mixture of.

(a) 4.25 ×10^-4  M  
(b) 2.78 ×10^-2  M
(c) 2.30 × 10^-3 M
(d) 1.35 ×10^-2 M

16. A button cell used in watches functions as following:
Zn(s) + Ag₂ O(s) + H₂ O(l) 2 Ag(s)+Zn²⁺ (aq)+2OH^– (aq)
If half-cell potentials are:
Zn²⁺(aq) + 2e^– → Zn(s) E° = – 0.76V
Ag₂O(s) + H₂ O(l)+2e^–→2Ag(s)+20H_– (aq), E° = 0.34 V
The cell potential wil be:

(a) 1.10 V
(b) 0.42 V
(c) 0.84 V
(d) 1.34 V

17. The correct order of increasing bond length of C – H, C-O, C-C and C =C is:

(a) C – C < C = C < C – O < C – H
(b) C – O < C – H < C – C < c = C
(c) C – H < C – O < C – C < C = C
(d) C – H < C = C < C – O < C – C

18. Which one of the following orders is correct for the bond dissociation enthalpy of halogen molecules?

(a) Br₂ > I₂  > F₂ > Cl₂
(b) F₂ > Cl₂ > Br₂ >  I₂
(c) I₂ > Br₂ > Cl₂ > F₂
(d) Cl₂ > Br₂ > F₂ >  I₂

19. Gadolinium belongs to 4f series number is 64. Which of the following is the correct electronic configuration of gadolinium?

(a) [Xe]  4f⁸  6s²
(b) [Xe]  4f¹  5s¹
(c) [Xe]  4f⁷ 5d¹  6s²    
(d) [Xe]  4f⁶ 5d²  6s²

20. Propionic acid with Bry/P yields a dibromo product. Its structure would be: