Chemistry Physical Chemistry questions from NEET UG 2004.
Considering entropy (S) as a thermodynamic parameter, the criterion for the spontaneity of any process is:
If the bond energies of $\mathrm{H}-\mathrm{H}, \mathrm{Br}-\mathrm{Br}$, and $\mathrm{H}-\mathrm{Br}$ are 433,192 and $364 \mathrm{~kJ} /\mathrm{mol}^{-1}$ respectively, the $\Delta \mathrm{H}^{\circ}$ for the reaction $\mathrm{H}_{2(g)}+\mathrm{Br}_{2(g)} \rightarrow 2 \mathrm{HBr}_{(g)}$ is:
Standard enthalpy and standard entropy changes for the oxidation of ammonia at $298 \mathrm{~K}$ are $-382.64 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and -145.6 $\mathrm{JK}^{-1} \mathrm{~mol}^{-1}$, respectively. Standard Gibbs energy change for the same reaction at $298 \mathrm{~K}$ is:
The frequency radiation emitted when the electron falls from $\mathrm{n}=4$ to $n=1$ in a hydrogen atom will be (Given ionization energy of $\mathrm{H}=2.18 \times 10^{-18} \mathrm{~J} \mathrm{atom}^{-1}$ and $h$ $\left.=6.625 \times 10^{-34} \mathrm{Js}\right)$ :
The maximum number of molecules is present in:
The radioactive isotope ${ }_{27}^{60} \mathrm{Co}$ which is used in the treatment of cancer can be made by $(n, p)$ reaction. For this reaction the target nucleus is:
The rapid change of $\mathrm{pH}$ near the stoichiometric point of an acid base titration is the basis of indicator detection, $\mathrm{pH}$ of the solution is related to ratio of the concentration of the conjugate acid (Hln) and base $\left(\mathrm{In}^{-}\right)$forms of the indicator by the expression:
The rate of a first order reaction is $1.5 \times$ $10^{-2} \mathrm{~mol} \mathrm{~L}^{-1} \mathrm{~min}^{-1}$ at $0.5 \mathrm{M}$ concentration of the reactant. The half life of the reaction is:
The solubility product of a sparingly soluble salt $\mathrm{AX}_2$ is $3.2 \times 10^{-11}$. Its solubility (in moles/litre) is:
The standard e.m.f of a galvanic cell involving cell reaction with $\mathrm{n}=2$ is found to be $0.295 \mathrm{~V}$ at $25^{\circ} \mathrm{C}$. The equilibrium constant of the reaction would be: (Given $\mathrm{F}=96500 \mathrm{C} \mathrm{mol}^{-1}, \mathrm{R}=8.314 \mathrm{~J}$ $\mathrm{K}^{-1} \mathrm{~mol}^{-1}$
The work done during expansion of a gas from a volume of $4 \mathrm{dm}^3$ to $6 \mathrm{dm}^3$ against a constant external pressure of $3 \mathrm{~atm}$ is $(1 \mathrm{~L} \mathrm{~atm}=101.32 \mathrm{~J})$ :
Which is the best description of the behaviour of bromine in the reaction given below? $$ \mathrm{H}_2 \mathrm{O}+\mathrm{Br}_2 \rightarrow \mathrm{HOBr}+\mathrm{HBr} $$