Chemistry Physical Chemistry questions from NEET UG 2011.
A 0.1 molal aqueous solution of a weak acid is $30 \%$ ionised. If $K_f$ for water is $1.86^{\circ} \mathrm{C} / \mathrm{m}$, the freezing point of the solution will be
A buffer solution is prepared in which the concentration of $\mathrm{NH}_3$ is $0.30 \mathrm{M}$ and the concentration of $\mathrm{NH}_4^{+}$is $0.20 \mathrm{M}$. If the equilibrium constant, $K_b$ for $\mathrm{NH}_3$ equals $1.8 \times 10^{-5}$, what is the $\mathrm{pH}$ of this solution? $(\log 2.7=0.43)$
A gaseous mixture was prepared by taking equal moles of $\mathrm{CO}$ and $\mathrm{N}_2$. If the total pressure of the mixture was found 1 atmosphere, the partial pressure of the nitrogen $\left(\mathrm{N}_2\right)$ in the mixture is
A solution contains $\mathrm{Fe}^{2+}, \mathrm{Fe}^{3+}$ and $\mathrm{I}^{-}$ions. This solution was treated with iodine at $35^{\circ} \mathrm{C}$. $E^{\circ}$ for $\mathrm{Fe}^{3+} / \mathrm{Fe}^{2+}$ is $+0.77 \mathrm{~V}$ and $\mathrm{E}^{\circ}$ for $\mathrm{I}_2 / 2 \mathrm{I}^{-}=0.536 \mathrm{~V}$. The favourable redox reaction is
According to the Bohr theory, which of the following transitions in the hydrogen atom will give rise to the least energetic photon?
By what factor does the average velocity of a gaseous molecule increase when the temperature (in Kelvin) is doubled?
Consider the following processes $\Delta H(\mathrm{~kJ} / \mathrm{mol})$ $\begin{array}{ll}1 / 2 A \rightarrow B & +150 \\ 3 B \rightarrow 2 C+D & -125 \\ E+A \rightarrow 2 D & +350\end{array}$ For $B+D \rightarrow E+2 C, \Delta H$ will be
For the reaction, \(\mathrm{N}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NO}(\mathrm{g})\), the equilibrium constant is \(\mathrm{K}_1\). The equilibrium constant is \(\mathrm{K}_2\) for \(2 \mathrm{NO}(\mathrm{g})+\mathrm{O}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NO}_2(\mathrm{~g})\). What is K for the reaction \(\mathrm{NO}_2(\mathrm{~g}) \rightleftharpoons \frac{1}{2} \mathrm{~N}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) ?\)
If $x$ is amount of adsorbate and $m$ is amount of adsorbent, which of the following relations is not related to adsorption process?
If the enthalpy change for the transition of liquid water to steam is $30 \mathrm{~kJ} \mathrm{~mol}^{-1}$ at $27^{\circ} \mathrm{C}$, the entropy change for the process would be
In qualitative analysis, the metals of group I can be separated from other ions by precipitating them as chloride salts. A solution initially contains $\mathrm{Ag}^{+}$and $\mathrm{Pb}^{2+}$ at a concentration of $0.10 \mathrm{M}$. Aqueous $\mathrm{HCl}$ is added to this solution until the $\mathrm{Cl}^{-}$concentration is $0.10 \mathrm{M}$. What will be the concentration of $\mathrm{Ag}^{+}$and $\mathrm{Pb}^{2+}$ be at equilibrium? ( $K_{\mathrm{sp}}$ for $\mathrm{AgCl}=1.8 \times 10^{-10}, K_{\mathrm{sp}}$ for $\mathrm{PbCl}_2=1.7 \times 10^{-5}$ )
Mole fraction of the solute in a 1.00 molal aqueous solution is
$200 \mathrm{~mL}$ of an aqueous solution of a protein contains its $1.26 \mathrm{~g}$. The osmotic pressure of this solution at $300 \mathrm{~K}$ is found to be $2.57 \times 10^{-3}$ bar. The molar mass of protein will be
Standard electrode potential for $\mathrm{Sn}^{4+} / \mathrm{Sn}^{2+}$ couple is $+0.15 \mathrm{~V}$ and that for the $\mathrm{Cr}^{3+} / \mathrm{Cr}$ couple is -0.74 . These two couples in their standard state are connected to make a cell. The cell potential will be
Standard electrode potential of three metals $X, Y$ and $Z$ are $-1.2 \mathrm{~V},+0.5 \mathrm{~V}$ and $-3.0 \mathrm{~V}$ respectively. The reducing power of these metals will be
The electrode potentials for $\begin{aligned} & \mathrm{Cu}^{2+}(a q)+e^{-} \longrightarrow \mathrm{Cu}^{+}(a q) \\ & \text { and } \mathrm{Cu}^{+}(a q)+e^{-} \longrightarrow \mathrm{Cu}(s) \\ & \text { are }+0.15 \mathrm{~V} \text { and }+0.50 \mathrm{~V} \text { respectively. The value } \\ & \text { of } E_{\mathrm{Cu}^{2+} / \mathrm{Cu}}^{\circ} \text { will be } \end{aligned}$
The energies $E_1$ and $E_2$ of two radiations are $25 \mathrm{eV}$ and $50 \mathrm{eV}$ respectively. The relation between their wavelengths i.e., $\lambda_1$ and $\lambda_2$ will be
The freezing point depression constant for water is $-1.86^{\circ} \mathrm{C} \mathrm{m}^{-1}$. If $5.00 \mathrm{~g} \mathrm{Na} \mathrm{SO}_4$ is dissolved in $45.0 \mathrm{~g} \mathrm{H}_2 \mathrm{O}$, the freezing point is changed by $-3.82^{\circ} \mathrm{C}$. Calculate the van't Hoff factor for $\mathrm{Na}_2 \mathrm{SO}_4$.
The half-life of a substance in a certain enzyme-catalysed reaction is $138 \mathrm{~s}$. The time required for the concentration of the substance to fall from $1.28 \mathrm{mg} \mathrm{L}^{-1}$ to $0.04 \mathrm{mg} \mathrm{L}^{-1}$ is
The rate of reaction $2 \mathrm{~N}_2 \mathrm{O}_5 \longrightarrow 4 \mathrm{NO}_2+\mathrm{O}_2$ can be written in three ways $\begin{aligned} \frac{-d\left[\mathrm{~N}_2 \mathrm{O}_5\right]}{d t} & =k\left[\mathrm{~N}_2 \mathrm{O}_5\right] \\ \frac{d\left[\mathrm{NO}_2\right]}{d t} & =k^{\prime}\left[\mathrm{N}_2 \mathrm{O}_5\right] \\ \frac{d\left[\mathrm{O}_2\right]}{d t} & =k^{\prime \prime}\left[\mathrm{N}_2 \mathrm{O}_5\right] \end{aligned}$ The relationship between $k$ and $k^{\prime}$ and between $k$ and $k^{\prime \prime}$ are
The total number of atomic orbitals in fourth energy level of an atom is
The unit of rate constant for a zero order reaction is
The value of $\Delta H$ for the raction $X_2(g)+4 Y_2(g)^{39} 2 X Y_4(g)$ is less than zero. Formation of $X Y_4(g)$ will be favoured at
The van't Hoff factor, $i$ for a compound which undergoes dissociation in one solvent and association in other solvent is respectively.
Two gases $A$ and $B$ having the same volume diffuse through a porous partition in 20 and 10 seconds respectively. The molecular mass of $A$ is $49 \mathrm{u}$. Molecular mass of $B$ will be
Which has the maximum number of molecules among the following?
Which of the following is correct option for free expansion of an ideal gas under adiabatic condition?
Which one of the following statements for the order of a reaction is incorrect?
Which one of the following statements is not true?