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11 months ago

Class 12th Some Basic Concepts of Chemistry

A commercially sold conc. HCl is 35% HCl by mass. If the density of this commercial acid is 1.46 g/mL, the molarity of this solution is

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Payal Gupta

Contributor-Level 10

$M o l a l i t y = \frac{m o l e s o f s o l u t e * 1000}{w t o f s o l v e n t (g m)}$

$M o l a l i t y = \frac{35 * 1000 * 1.46}{36.5 * 100}$ = 14.0 M

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11 months ago

Class 12th Dual Nature of Radiation and Matter

An ideal fluid of density 800kgm^-3, flows smoothly through a bent pipe (as shown in figure) that tapers in cross-sectional area from a to $\frac{a}{2} .$ The pressure difference between the wide and narrow sections of pipe is 4100 Pa. At wider section, the velocity of fluid is $\frac{\sqrt[]{x}}{6} m s^{- 1}$ for x =________. (Given g = 10 ms^-²)

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Payal Gupta

Contributor-Level 10

$ρ = 800 k g / m^{3}$

P₁ – P₂ = 4100 Pa

Bernoulli's question b/w (1) & (2)

$\frac{P_{1}}{ρ g} + \frac{v_{1}^{2}}{2 g} + z_{1} = \frac{P_{2}}{ρ g} + \frac{v_{2}^{2}}{2 g} + z_{2}$

$\frac{P_{1} - P_{2}}{ρ g} + \frac{v_{1}^{2}}{2 g} + 1 = \frac{v_{2}^{2}}{2 g} + 0$ -(1)

Equation of continuity

A₁v₁ = A₂v₂

v₂ = 2v₁-(2)

from (1) & (2)

$\Rightarrow \frac{P_{1} - P_{2}}{ρ g} + \frac{v_{1}^{2}}{2 g} + 1 = \frac{{(2 v_{1})}^{2}}{2 g}$

$\frac{4100}{800 * 10} + \frac{v_{1}^{2}}{2 g} + 1 = \frac{4 v_{1}^{2}}{2 g}$

$\frac{12100}{8000} = \frac{3 v_{1}^{2}}{2 g}$

$\Rightarrow v_{1}^{2} = \frac{2 * 10}{3} * \frac{12100}{8000}$

$= \frac{2}{3} * \frac{121}{8}$

x = 363

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11 months ago

Class 12th Chemistry NCERT Exemplar Solutions Class 12th Chapter Eleven

Given below are two statements:

Statement I : Phenols are weakly acidic

Statement II : Therefore they are freely soluble in NaOH solution and are weaker acids than alcohols and water

Choose the most appropriate options:

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alok kumar singh

Contributor-Level 10

Phenol is weakly acidic compound but it is more acidic than alcohol and water because its conjugate base is more stable. Hence statement -I is correct while statement -II is wrong.

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11 months ago

Class 12th Thermodynamics

A 110 V, 50Hz, AC source is connected in the circuit (as shown in figure). The current through the resistance $55 Ω,$ at resonance in the circuit, will be__________A.

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Payal Gupta

Contributor-Level 10

At Resonance

X_L = X_C

then l_L = l_C

Now phasor diagram

for L & C

So, Net current = zero

$= (l_{L} + l_{C})$

Therefore current through R circuit at resonance will be zero

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11 months ago

Class 12th Chemistry NCERT Exemplar Solutions Class 12th Chapter Sixteen

Which of the following compound does not contain sulfur atom?

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alok kumar singh

Contributor-Level 10

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11 months ago

Class 12th Chemistry NCERT Exemplar Solutions Class 12th Chapter Fourteen

Sugar moiety in DNA and RNA molecules respectively are

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alok kumar singh

Contributor-Level 10

DNA contains b-D-2- deoxyribose sugar while RNA contains b-D-ribose.

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11 months ago

Class 12th Electromagnetic Induction

As per the given circuit, the value of current through the battery will be__________A.

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Payal Gupta

Contributor-Level 10

$\begin{array}{l} D_{1} \\ D_{3} \end{array}}$ Forward biased offer zero Resistance

D₂} Reversed biased offers Infinite Resistance

$I = \frac{v}{R} = \frac{10}{10} = 1 A m p$

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11 months ago

Class 12th Chemistry NCERT Exemplar Solutions Class 12th Chapter Fifteen

The polymer, which can be stretched and retains its original status on releasing the force is

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alok kumar singh

Contributor-Level 10

Buna – N is synthetic rubber which can be stretched and retains its original status on releasing the force.

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11 months ago

Class 12th Oscillations

In a vernier calipers, each cm on the main scale is divided into 20 equal parts. If tenth vernier scale division coincides with nineth main scale division. Then the value of vernier constant will be__________* 10^-2mm.

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Payal Gupta

Contributor-Level 10

Let 'x' he the value of one division of main scale

$x = \frac{1}{20} c m = 0.05 c m$

Let y be value of one division on venire scale given

10 y = 9 x

$y = \frac{9 x}{10}$

Least count = $x - \frac{9 x}{10} = \frac{x}{10} = \frac{0.05}{10}$

= 0.005 cm

= 5 * 10^-2 mm

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11 months ago

Class 12th Ray Optics and Optical Instruments

A light ray is incident, at an incident angle q₁, on the system of two plane mirrors M₁ and M₂ having an inclination angle 75° between them (as shown in figure). After reflecting from mirror M₁ it gets reflected back by the mirror M₂ with an angle of reflection 30°. The total deviation of the ray will be ___________ degree.

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Payal Gupta

Contributor-Level 10

$δ_{t o t a l} = 360 ° - 2 θ$

= 360 – 2 * 75° = 210°

Total deviation = $δ = 150 °$

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