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Correct option (4) Only the assertion is correct.

Explanation:

Extration fo Fe is done from Haematite or this is true but reason is strong as Haematitte is Fe₂O₃.

Correct option (3) 8

Explanation:

Work done on system = +10 kT

Heat escaped = –2kI 

ΔU = q + w

= 10 – 2 = 8 KJ

Correct option  (3)  (A) → (R); (B) → (P); (C) → (Q); (D) →(S)

Informative

Correct option:  (4) ZnO and MgO

Explanation:

ZnO and MgO both are in oxide form so there is no change on calcination of ZnO and MgO whereas carbonate decompose into oxide and CO₂ on calcination.

The correct option is (2).

Explanation:

The electrolytes usually used in the electroplating of gold & silver, respectively are :

[Au(CN)₂]θ and [Ag(CN)₂]θ

Correct option  (2) m = n = 78

Explanation:

Given : (8 males, 5 females)

Committee to be selected = 11 members

m = no. of ways the committee is formed with at least 6 males.

⇒ (6M, 5F) or (7M, 4F) or (8M, 3F)

= ⁸C₆ × ⁵C₅ + ⁸C₇ × ⁵C₄ + ⁸C₈ × ⁵C₃ = 78

n = no. of ways the committee is formed with atleast 3 female 

⇒(8M, 3F) or (7M, 4F) or (6M, 5F)

= ⁸C₈ × ⁵C₃ + ⁸C₇ × ⁵C₄ + ⁸C₆ × ⁵C₅ 

= 10 + 40 + 28 = 78 

⇒m = n = 78

Correct option: (4)

Explanation:

NaBH₄ does not reduces ester functional group.

The correct option (3) 25/32  

Explanation:

P(H) = 1 - P(Not Hitting)

= 1 - 1/2 x 2/3 x 3/4 x 7/8 = 25/32

Correct option: (3) ~ p ∧ ~ q 

Explanation:

~(~p → q) 

= ~p ∧ ~q 

Correct option  (1) –25 

Explanation:

Let the three numbers in A.P. are 

a – d, a, a + d

given that : a – d + a + d = 33

⇒ a = 11

and (a – d)(a)(a + d) = 1155

⇒ a(a² – d² ) = 1155

⇒ 11(121 – d² ) = 1155

⇒ d² = 16

⇒ d = ±4

If d = 4 then first term a – d = 7 

If d = –4 then first term a – d = 15 

T₁₁ = 7 + 10(4) = 47

or T₁₁ = 15 + 10(–4) = –25

 (b) 3600''

Explanation:

1° = 6'

and     1' = 6''

hence 1° = 60' = 60 × 60'' = 3600''  

(d) 10⁶  

Explanation:

1 MeV = 1 × 10⁶ eV 

Correct Answer is: (c) 2.5 Hz

The duration of one beat is from one maximum to the next maximum of intensity. In this case, it is 0.4 s.

∴ the number of beats per second = 2.5 = the difference in frequencies. 

Correct Answer is: (d) 2μg

The only horizontal forces acting on the two bodies are those due to friction of magnitude μmg each, in opposite directions. Hence, they have accelerations μg each, in opposite directions.

Correct Answer is: (c) E = 2E₀, I = 4I₀ 

Correct Answer is: (d) 1 : 25

Given \(\frac{N_2}{N_1}=1.6\times10^{-29}\)

At the thermal equilibrium the ratio

\(\frac{N_2}{N_1} \) = exp(\(\frac{-E_2-E_1}{KT}\))

\(\because\) E₂ - E₁ = \(\frac{hc}\lambda\) 

1.6 x 10^-29 = exp(\(\frac{-hc}{\lambda KT}\))

ln(1.6 x 10^-29) = \(\frac{-hc}{\lambda KT}\)

ln(1.6) - 29ln(10) = \(-\frac{hc}{\lambda kT}\) 

0.470 - 29 x 2.30 = \(-\frac{hc}{\lambda KT}\)

0.470 - 66.7 = \(\frac{-hc}{\lambda KT}\)

-66.23 = \(\frac{-hc}{\lambda KT}\) 

\(\lambda = \frac{6.626\times10^{-34}\times3\times10^8}{1.38\times10^{-23}\times303\times66.23}\) 

\(\lambda=\frac{19.87\times10^{-26}}{27693.41\times10^{-23}}\) 

⇒ 0.000717 x 10^-3

=  717 x 10^-9 m

Correct option (3) K

Explanation:

K has 4s' configuratioon 

∴ after removal of outermost 

e ^– it aquire inert gas conf. 

∴ Greatest jump in I.E is observes

Correct option (1) (a), (b), (c) and (d)   

Explanation:

Statement a, b, c and d are the correct statements as per the facts

The correct option is (4) (a), (b) and (c) only.

The correct option is (2).

Explanation:

As we move from L --> R, Atomic size decrease and while as we move from top to bottom, atomic size increase. 

The correct option is (2).

Explanation:

In cold water, dissolved oxygen (DO) can reach a concentration upto 10 ppm.

Correct option: (3)

Explanation:

Low polarity compounds are weekly adsorbed and has greater Rf value.

Correct option (3) Differential adsorption of the substances on the solid phase.

Explanation:

The principle of column chromatography is differential adsorption of substance and hence option on 3 is correct. 

Correct option is (3) b, c

Micelle formation is spontaneous therefore △S > 0.

Micelle formation decrease stability of colloidal solution so enthalpy should be positive △H > 0

The world faced a drastic change after the second world war. America to protect vested interests of imperialism and Soviet Union to protect socialistic ideas. Soviet Union could protect the world from American imperialism. Soviet Union was able to protect the interest of Egypt in the Suez Canal Crisis. Also, Soviet Union stood for justice in the Cuban Crisis and in the conflict on Kashmir between India and Pakistan.

But Soviet Union lost its power in the year 1991. Deviation from the basic principle of socialism and the external intervention as a part of globalization was the reason for the disintegration. The policies of Michael Gorbachev, the President, took Soviet Union to Imperialism.

Correct option is (C) B and C only

For micelle formation, DS > 0 (hydrophobic effect) This is possible because, the decrease in entropy due to clustering is offset by increase in entropy due to desolvation of the surfactant, Also DH > 0 6. 

• Deviation from the basic principles of socialism. 
• The administrative measures of Mikhail Gorbachev – Glasnost and Perestroika.
• Corruption and inefficiency of the bureaucracy. 
• Failure in bringing about changes in economic sector.

In the absence of a socialist bloc, policies and programmes of the capitalist countries remained unquestioned. This had a wide impact on international relations. A unipolar world emerged under the leadership of USA instead of a bipolar world.