Ncert Solutions Chemistry Class 11th

Which of the following compound is added to the sodium extract before addition of silver nitrate for testing of halogens?

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NaCN converted into HCN and Na₂S converted into H₂S

$\begin{array}{l} N a C N + H N O_{3} \to N a N O_{3} + H C N \\ N a_{2} S + 2 H N O_{3} \to N a N O_{3} + H_{2} S \end{array}$

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The correct order of bond dissociation enthalpy of halogens is

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Bond dissociation enthalpy is the energy required to break 1 mole of bond according to experimental data

Bond energy : Cl₂ > Br₂ > F₂ > l₂

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The solubility of Ca(OH)₂ in water is:

[Given : The solubility product of Ca(OH)₂ in water = 5.5 * 10^-6]

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Using the provided information in the following paper chromatogram: Fig : Paper chromatography for compounds A and B. The calculated R_f value of A------------* 10^-1

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$R_{f} v a l u e = \frac{D i s t a n c e m o v e d b y s u b s t a n c e f r o m b a s e l i n e}{D i s t a n c e m o v e d b y t h e s o l v e n t f r o m b a s e l i n e} = \frac{2}{5} = 0.4 = 4.0 * 1 0^{- 1}$

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The ionization enthalpy of Na⁺ formation from Na_(g)is 495.8 kJ mol^-1, while the electron gain enthalpy of Br is - 325.0 kJ mol^-1. Given the lattice enthalpy of NaBr is - 728.4 kJ mol^-1. The energy for the formation of NaBr ionic solid is (-) -------------- * 10^-1kJ mol^-1.

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Δ H_{s u b} o f N a m e t a l = 496 k J / m o l e

Bond dissociation energy of Br₂ = 228 kJ/mole

$Δ H_{f} = 495.8 + - 325 - 728.4 = - 557.6 k J / m o l e = - 5576 * 1 0^{- 1} k J / m o l e$

Note : In question is neglect $Δ_{a} H^{0} o f N a, Δ_{v a p} H^{O} o f B r_{2} (l) a n d Δ_{b o n d} H^{0} o f B r_{2} (g)$

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Bond dissociation energy of Br₂ = 228 kJ/mole

$? H_{f} = 495.8 + ? 325 ? 728.4 = ? 557.6 k J / m o l e = ? 5576 * 1 0^{? 1} k J / m o l e$

Note : $?_{a} H^{0} ? ? o f ? ? N a, ?_{v a p} H^{O} o f ? ? B r_{2} (l) a n d ? ? ?_{b o n d} H^{0} ? ? o f ? ? B r_{2} (g)$ In question is neglected

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A car tyre is filled with nitrogen gas at 35 psi at 27°C. It will burst if pressure exceeds 40 psi. The temperature in °C at which the car tyre will burst is--------------. (Rounded – off to the nearest integer)

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$\frac{P_{1}}{T_{1}} = \frac{P_{2}}{T_{2}} \Rightarrow \frac{35}{300} = \frac{40}{T_{2}}$

$∴ T_{2} = \frac{40 * 300}{35} = 342.85 K$

$T_{2} (° C) = 69.707 \approx 70 ° C$

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The reaction of cyanamide, NH₂CN_(s) with oxygen was run in a bomb calorimeter and $Δ U$ was found to be -742.24 kJ mol^-1. The magnitude of $Δ H_{298}$ for the reaction

------------- kJ. (Rounded off to the nearest integer)

[Assume ideal gases and R = 8.314 J mol^-1 K^-1]

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$? U = ? 742.24 ? k J / m o l e ? H_{298} = ?$

NH₂CN (s) + $\frac{3}{2}$ O₂ (g) ® N₂ (g) + O₂ (g) + H₂O (l)

= $? 742.24 + \frac{1}{2} * \frac{8.314}{1000} * 298$

$? 742.24 + 1.238 = ? 741.002 ? ? 741 k J / m o l$

So, magnitude of $? H$ = 741 kJ/mol.

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Match List I with List II.

List-I List-II

(Process) &nbs

...more

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(A) Isothermal process $\Rightarrow$ Temperature is constant throughout the process

(B) Isochoric process $\Rightarrow$ Volume is constant throughout the process

(D) Adiabatic process $\Rightarrow$ No exchange of heat $(q)$ between system and surrounding

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For the reaction $2 A ? B + C, K_{C} = 4 * 1 0^{- 3}$ . At a given time, the composition of reaction mixture is: $[A] = [B] = [C] = 2 * 1 0^{- 3} M$ . Then, which of the following is correct?

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