JEE Main 2020 Shift 1- Sept 6th Chemistry solved questions are available at BYJU’S. Students can also download these solutions from our website in PDF format. Practising sample question papers help the candidates to get an idea of the weightage given to various topics, solve questions faster and learn time management. It also helps to understand the question paper pattern and to get an idea about the questions frequently asked in the examination.
1. The INCORRECT statement is:
Solution:
Answer: 2
Brass - (copper Zinc)
Bronze - (copper tin)
2. The species that has a spin-only magnetic moment of 5.9 BM, is: (T_{d}= tetrahedral)
Solution:
Answer: 3
[MnBr_{4}]^{2–}
3. For the reaction
Solution:
Answer: 1
Δn_{g} =1-3/2 = -1/2
(K_{p}/K_{c})= (RT)^{Δng} = (RT^{)-1/2}
K_{c}= K_{p}/(RT^{)-1/2} = K_{p}.(RT)^{1/2}
4. Consider the following reactions:
'A' is:
Solution:
5. Arrange the following solutions in the decreasing order of pOH:
(A) 0.01 M HCl
(B) 0.01 M NaOH
(C) 0.01 M CH3COONa
(D) 0.01 M NaCl
Solution:
Answer: 4
(i) 10^{–2} M HCl ⇒ [H^{+}] = 10^{–2} M → pH = 2
(ii) 10^{–2} M NaOH ⇒ [OH–] = 10^{–2} M → pOH = 2
(iii) 10^{–2} M CH_{3}COO^{–}Na^{+}⇒ [OH^{+}] > 10^{–7} ⇒ pOH < 7
(iv) 10^{–2} M NaCl ⇒ Neutral pOH = 7
(i) > (iv) > (iii) > (ii)
6. The variation of equilibrium constant with temperature is given below :
Temperature Equilibrium Constant
T_{1}= 25^{0}C K_{1}= 10
T_{2}= 100^{0}C K_{2}= 100
The value of ∆H^{0} , ∆G^{0} at T_{1} and ∆G^{0} at T_{2} (in Kj mol^{-1}) respectively, are close to
[use R = 8.314JK-1 mol-1]
Solution:
Answer: 3
∆G^{0}_{T1 }= –RT_{1}ln(K_{1}) = –298R ln(10) = –5.71 kJ mol^{–1}
∆G^{0}_{T2}= –RT2ln(K_{2}) = –373R ln(100)
= –14.283 kJ/mol
7. Consider the following reactions
A→ P1; B→ P2; C→ P3; D →P4,
The order of the above reactions are a,b,c and d, respectively. The following graph is obtained when log[rate] vs. log[conc.] are plotted.
Among the following the correct sequence for the order of the reactions is:
Solution:
Answer: 3
A→ P1; B→ P2; C→ P3; D →P4,
Rate= K(conc)^{order}
8. The major product obtained from the following reactions is:
Solution:
Solution
9. Which of the following compounds shows geometrical isomerism?
Solution:
10. The lanthanoid that does NOT shows +4 oxidation state is:
Solution:
Answer: 4
Fact
11. The major products of the following reactions are:
Solution:
12. The major product of the following reaction is:
Solution:
13. The increasing order of pK_{b} values of the following compounds is:
Solution:
14. kraft temperature is the temperature :
Solution:
Answer: 3
T_{K}^{+ } temp. above which formation of micelles takes place.
15. The set that contains atomic numbers of only transition elements, is?
Solution:
Answer: 2
Tranition elements = 21 to 30
37 to 48
57 & 72 to 80
Ans. 21, 25, 42 & 72
16. Consider the Assertion and Reason given below.
Assertion (A): Ethene polymerized in the presence of Ziegler Natta Catalyst at high temperature and pressure is used to make buckets and dustbins.
Reason (R): High density polymers are closely packed and are chemically inert. Choose the correct answer from the following:
Solution:
Answer: 2
From ziegler - Natta catalyst HDPE is produced, HDPE is closely packed and are chemically inert, so used to make backet and dust.
17. A solution of two components containing n_{1} moles of the 1^{st} component and n_{2} moles of the 2^{nd} component is prepared. M_{1} and M_{2} are the molecular weights of component 1 and 2 respectively. If d is the density of the solution in g mL^{-1}, C_{2} is the molarity and x_{2} is the mole fraction of the 2^{nd} component, then C_{2 }can be expressed as:
Solution:
Answer: 4
18. The correct statement with respect to dinitrogen is?
Solution:
Answer: 4
(1) Liquid nitrogen is used as a refrigerant to preserve biological material food items and in cryosurgery.
(2) N_{2} is diamagnetic, with no unpaired elctrons.
(3) N_{2} does not combine with oxygen, hydrogen or most other elements. Nitrogen will combine with oxygen, however; in the presence of lightining or a spark.
(4) In iron and chemical Industry inert diluent for reactive chemicals.
19. Among the sulphates of alkaline earth metals, the solubility of BeSO_{4} and MgSO_{4} in water, respectively, are:
Solution:
Answer: 2
Order of solubility of sulphate of Alkaline earth metals
BeSO_{4}> MgSO_{4} > CaSO_{4} > SrSO_{4}> BaSO_{4}
20. The presence of soluble fluoride ion upto 1ppm concentration in drinking water, is:
Solution:
Answer: 3
Environmental chemistry - safe for teeth
21. A spherical balloon of radius 3cm containing helium gas has a pressure of 48 × 10^{-3} bar. At the same temperature, the pressure, of a spherical balloon of radius 12cm containing the same amount of gas will be.........................× 10^{-6} bar.
Solution:
Answer: 750
P × 144 × 12 = 48 × 9 × 3 × 10^{–3}
P = (27/36) x 10^{-3}
P = 750 × 10^{–6} bar
22. The elevation of boiling point of 0.10m aqueous CrCl_{3} xNH_{3} solution is two times that of 0.05 m aqueous CaCl_{2} solution. The value of x is.................
[Assume 100% ionisation of the complex and CaCl_{2}, coordination number of Cr as 6, and that all NH_{3} molecules are present inside the coordination sphere]
Solution:
Answer: 5
∆Tb = i × K_{b} × m
i × 0.1 × K_{b} = 3 × 0.05 × K_{b} × 2
i = 3
[Cr(NH_{3})_{5}. Cl] Cl_{2} →[Cr(NH_{3})_{5}Cl]^{+2} + 2Cl^{–}
x = 5
23. Potassium chlorate is prepared by the electrolysis of KCl in basic solution
6OH^{–} + Cl^{–} -> ClO_{3}^{–} + 3H_{2}O + 6e^{–}
If only 60% of the current is utilized in the reaction, the time (rounded to the nearesthour) required to produce 10g of KClO_{3} using a current of 2A is .............
(Given: F = 96,500 C mol^{-1}; molar mass of KClO_{3}=122g mol^{-1})
Solution:
Answer: 11
t(hr) =
= 11 hours
24. In an estimation of bromine by Carius method, 1.6 g of an organic compound gave 1.88 g of AgBr. The mass percentage of bromine in the compound is....... .(Atomic mass, A_{g}=108, Br=80 g mol^{–1})
Solution:
Answer: 50 %
Carius method
= (1.88/1.6) x (80/188) x 100 = 15040/300.8 = 50 %
25. The number of Cl = O bonds in perchloric acid is, "..............."
Solution:
Answer: 3