Physical Chemistry PYQ — Page 52

The strength of an aqueous $NaOH$ solution is most accurately determined by titrating: (Note: consider that an appropriate indicator is used)

If the equilibrium constant for $A\rightleftharpoons B+C$ is ${K}_{\mathrm{eq}}^{(1)}$ and that of $B+C\rightleftharpoons P$ is ${K}_{\mathrm{eq}}^{(2)},$ the equilibrium constant for $A\rightleftharpoons P$ is :

A flask contains a mixture of compounds $A$ and $B$. Both compounds decompose by first-order kinetics. The half-lives for $A$ and $B$ are $300s$ and $180s$, respectively. If the concentrations of $A$ and $B$ are equal initially, the time required for the concentration of A to be four times that of $B$ (in s) is : $(\mathrm{Use}\mathrm{ln}2=0.693)$

Lattice enthalpy and enthalpy of solution of $\mathrm{NaCl}$ are $788{\mathrm{kJmol}}^{-1}$and $4kJmol{}^{-1}$, respectively. The hydration enthalpy of $NaCl$is:

In the figure shown below reactant $A$ (represented by square) is in equilibrium with product $B$ (represented by circle). The equilibrium constant is (approx): 

Arrange the following solutions in the decreasing order of pOH : (A) $0.01\mathrm{MHCl}$ (B) $0.01\mathrm{MNaOH}$ (C) $0.01{\mathrm{MCH}}_{3}\mathrm{COONa}$ (D) $0.01\mathrm{MNaCl}$

In the sixth period, the orbitals that are filled are :

If $250{\mathrm{cm}}^{3}$of an aqueous solution containing $0.73g$ of a protein $A$ is isotonic with one litre of another aqueous solution containing $1.65g$ of a protein $B,$ at $298K$, the ratio of the molecular masses of $A$ and $B$ is $___________\times {10}^{-2}$ (to the nearest integer).

For the reaction $2{H}_{2}(g)+2NO(g)\rightarrow {N}_{2}(g)+2{H}_{2}O(g)$ the observed rate expression is, rate $={k}_{f}{[\mathrm{NO}]}^{2}[{H}_{2}]$ . The rate expression for the reverse reaction is:

The rate constant $(k)$ of a reaction is measured at different temperature $(T)$, and the data are plotted in the given figure. the activation energy of the reaction in ${\mathrm{kJmol}}^{-1}$ is : $(R$ is gas constant) 

The correct statement about probability density (except at infinite distance from nucleus) is :

A $20.0\mathrm{mL}$ solution containing $0.2g$ impure ${H}_{2}{O}_{2}$ reacts completely with $0.316g$ of ${\mathrm{KMnO}}_{4}$ in acid solution. The purity of ${H}_{2}{O}_{2}$ (in $%$) is______ (mol. wt. of ${H}_{2}{O}_{2}=34$; mol. wt. of ${\mathrm{KMnO}}_{4}=158$)

The ammonia $({NH}_{3})$ released on quantitative reaction of $0.6 g$ urea $({NH}_{2}CON{H}_{2})$ with sodium hydroxide $(NaOH)$ can be neutralized by

The volume, in $\mathrm{mL}$, of $0.02{\mathrm{MK}}_{2}{\mathrm{Cr}}_{2}{O}_{7}$, solution required to react with $0.288g$ of ferrous oxalate in acidic medium is$\ldots \ldots \ldots \ldots$ (Molar mass of $\mathrm{Fe}=56{\mathrm{gmol}}^{-1}$ )

Two open beakers one containing a solvent and the other containing a mixture of that solvent with a non volatile solute are together sealed in a container. Over time:

The standard heat of formation $({\Delta }_{f}{H}_{298}^{0})$ of ethane (in $kJ/mol$ ), if the heat of combustion of ethane, hydrogen and graphite are $-1560,-393.5$ and $-286 kJ/mol$ , respectively is ________

A $100\mathrm{mL}$ solution was made by adding $1.43g$ of ${\mathrm{Na}}_{2}{\mathrm{CO}}_{3}.{\mathrm{xH}}_{2}O.$ The normality of the solution is $0.1N$. The value of $x$ is _______ (The atomic mass of $\mathrm{Na}$ is $23g/\mathrm{mol}$)

An acidic buffer is obtained on mixing:

The ratio of the mass percentages of '$C$ & $H$' and '$C$ & $O$' of a saturated acyclic organic compound '$X$' are $4:1$ and $3:4$ respectively. Then, the moles of oxygen gas required for complete combustion of two moles of organic compound '$X$' is_______

$3 g$ of acetic acid is added to $250 mL$ of $0.1 MHCl$ and the solution made up to $500 mL$. To $20 mL$ of this solution $\frac{1}{2 }mL$ of $5MNaOH$ is added. The $pH$ of the solution is ________ [Given: $pKa$ of acetic acid $=4.75,$ molar mass of acetic acid $60 g/mol,\mathrm{log}⁡3=0.4771$ , Neglect any changes in volume]

The results given in the below table were obtained during kinetic studies of the following reaction: $2A+B\rightarrow C+D$ <table class="pyq-table"><tbody><tr><td>Experiment</td><td>$[A]/{\mathrm{molL}}^{-1}$</td><td>$[B]/{\mathrm{molL}}^{-1}$</td><td>Initial rate/${\mathrm{molL}}^{-1}{\mathrm{min}}^{-1}$</td></tr><tr><td>I</td><td>$0.1$</td><td>$0.1$</td><td>$6.00\times {10}^{-3}$</td></tr><tr><td>II</td><td>$0.1$</td><td>$0.2$</td><td>$2.40\times {10}^{-2}$</td></tr><tr><td>III</td><td>$0.2$</td><td>$0.1$</td><td>$1.20\times {10}^{-2}$</td></tr><tr><td>IV</td><td>X</td><td>$0.2$</td><td>$7.20\times {10}^{-2}$</td></tr><tr><td>V</td><td>$0.3$</td><td>Y</td><td>$2.88\times {10}^{-1}$</td></tr></tbody></table>X and Y in the given table are respectively :

If the solubility product of ${\mathrm{AB}}_{2}$ is $3.20\times {10}^{-11}{M}^{3}$, then the solubility of ${\mathrm{AB}}_{2}$ in pure water is _______ $\times {10}^{-4}\mathrm{mol}{L}^{-1}$ [Assuming that neither kind of ion reacts with water]

Consider the following reactions: $\text{NaCl}+{\text{K}}_{2}{\text{Cr}}_{2}{\text{O}}_{7}+\underset{(\text{Conc.})}{{\text{H}}_{2}{\text{SO}}_{4}}\rightarrow (\text{A})+$ side products $(A)+NaOH\rightarrow (B)+$ side products $(B)+\underset{(\text{dilute})}{{H}_{2}S{O}_{4}}+{H}_{2}{O}_{2}\rightarrow (C)+$ side products The sum of the total number of atoms in one molecule each of $(A),(B)$ and $(C)$ is ________

A set of solutions is prepared using $180g$ of water as a solvent and $10g$ of different non-volatile solutes $A,B$ and $C$. The relative lowering of vapour pressure in the presence of these solutes are in the order [Given, molar mass of $A=100g{\mathrm{mol}}^{-1};B=200g{\mathrm{mol}}^{-1};C=10,000g{\mathrm{mol}}^{-1}$]