Class 12th

Water sample is called cleanest on the basis of which one of the BOD values given below:

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BOD is biological oxygen demand which represents the amount of oxygen required to degrade organic matter in water.

Higher the BOD more polluted the water is

So; here water sample with BOD = 3 ppm is the cleanest

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Class 12th English

Answer the questions on the basis of the information given below.

There are five friends P, Q, R, S and T. Two of them play table tennis while the other three play different games, viz. football, cricket and chess. One table tennis player and the chess player stay on the same floor while the other three stay on floors 2, 4 and 5. Two of the players are industrialists while the other three belong to different occupations viz. teaching, medicine and engineering. The chess player is the oldest while one of the table tennis players, who plays at the national level is the youngest. The other table tennis player who plays at the regional lev

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Class 12th Chemistry Electrochemistry

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Name	Game	Occupation	Floor	Age
P	Tennis	Industrialist	3	the youngest (1)
Q	Chess	Engineer	3	the oldest (5)
R	Football			6
S	Tennis		2	4
T	Crickets			2

From the above table, Correct answer is option (A)

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In the following sequence of reactions,

$C_{3} H_{6} \overset{H^{+} / H_{2} O}{\to} A \to_{d i l K O H}^{K Ι O} B + C$

The compounds B and C respectively are:

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Here, C₃H₆ is propene

Second reaction is iodoform reaction.

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In the electrolytic refining of blister copper, the total number of main impurities, from the following, removed as anode mud is _________.

Pb, Sb, Se, Te, Ru, Ag, Au and Pt

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Impurities present in electrolytic refining of blister Cu, removed as anode mud

= Sb, Se, Te, Ag, Au, Pt

Ans. = 6

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Number of paramagnetic oxides among the following given oxides is_________.

Li₂O, CaO, Na₂O₂, KO₂, MgO and K₂O

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Class 12th Chemical Kinetics

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Given are the oxide of alkali and alkaline earth metals which are ionic in nature.

Simple oxide are Li₂O, CaO, MgO and K₂O.

Peroxide is Na₂O₂ and superoxide is KO₂.

All simple oxides are diamagnetic as it has no unpaired electron.

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For the reaction A -> B, the rate constant K(in s^-1) is givne by

$l o g_{10} K = 20.35 - \frac{(2.47 * 1 0^{3})}{T} .$

The energy of activation in KJ mol^-1 is ______. (Nearest integer)

[Given : R = 8.314 J K^-1 mol^-1]

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log k = 20.35 - $\frac{(2.47 * 1 0^{3})}{T}$

Comparing with,

$l o g k = l o g A - \frac{E a}{2.303 R T}$

$\frac{E a}{2.303 R} = 2.47 * 1 0^{3}$

= 47.29 kJ/mole

Ans. = 47

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1.22 g of an organic acid is separately dissolved in 100 g of benzene (K_b = 2.6 K kg mol^-1) and 100 g of acetone (K_b = 1.7 K kg mol^-1). The acid is known to dimerize in benzene but remain as a monomer in acetone. The boiling point of the solution in acetone increases by 0.17°C. The increase in boiling point of solution in benzene in °C is x * 0^-2. The value of x is ________. (Nearest integer)

[Atomic mass : C = 12.0, H = 1.0, O = 16.0]

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$Δ T_{b} = i K_{b} m$ $_{}_{}$

$m = \frac{w * 1000}{M * W_{s o l v e n t}}$

For acetone solution,

$0.17 = 1 * 1.7 * \frac{1.22 * 1000}{M * 100}$

For Benzene solution,

$2 A c i d \to {(A c i d)}_{2} ∴ i = 1 / 2$

$Δ T_{b} = i * K_{b} * m$

$= \frac{1}{2} * 2.6 * \frac{1.22 * 1000}{122 * 100} ° C$

= $0.13 ° C = 13 * 1 0^{- 2} ° C$ $^{}$

$∴ x * 1 0^{- 2} = 13 * 1 0^{- 2}$

$∴ x = 13$

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The empirical formula for a compound with a cubic close packed arrangement of anions and with cations occupying all the octahedral sites is A_xB. The value of x is _______.

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