Enthalpy of a compound is equal to its

• heat of combustion

• heat of formation

• heat of reaction

• heat of solution

For which one of the following reactions will there be a positive $∆\mathrm{S}$?

• ${\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right) \to {\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

• ${\mathrm{H}}_2 + {\mathrm{I}}_2 \to 2\mathrm{HI}$

• ${\mathrm{CaCO}}_3\left(\mathrm{s}\right) \to \mathrm{CaO}\left(\mathrm{s}\right) + {\mathrm{CO}}_2\left(\mathrm{g}\right)$

• ${\mathrm{N}}_2\left(\mathrm{g}\right) + 3{\mathrm{H}}_2\left(\mathrm{g}\right)\to 2{\mathrm{NH}}_3\left(\mathrm{g}\right)$

A radioactive element X emits 3$\mathrm{\alpha }$, 1$\mathrm{\beta }$ and 1$\mathrm{\gamma }$-particles and forms ₇₆Y²³⁵. Element X is

• ₈₁X²⁴⁷

• ₈₀X²⁴⁷

• ₈₁X²⁴⁶

• ₈₀X²⁴⁶

4.

For the reaction,

$2\mathrm{A}\left(\mathrm{g}\right) + {\mathrm{B}}_2\left(\mathrm{g}\right) \rightleftharpoons 2{\mathrm{AB}}_2\left(\mathrm{g}\right)$ the equilibrium constant, K_P at 300K is 16.0. The value of K_P for

${\mathrm{AB}}_2\left(\mathrm{g}\right) \rightleftharpoons \mathrm{A}\left(\mathrm{g}\right) + 1/2{\mathrm{B}}_2\left(\mathrm{g}\right) \mathrm{is}$

• 8

• 0.25

• 0.125

• 32

The standard Gibb's free energy change, $∆$G° is related to equilibrium constant, K_p as

• ${\mathrm{K}}_{\mathrm{p}}= -\mathrm{RT} \ln ∆\mathrm{G}°$

• ${\mathrm{K}}_{\mathrm{p}}= {\left[\frac{\mathrm{e}}{\mathrm{RT}}\right]}^{∆\mathrm{G}°}$

• ${\mathrm{K}}_{\mathrm{p}}=-\frac{∆\mathrm{G}°}{\mathrm{RT}}$

• ${\mathrm{K}}_{\mathrm{p}}={\mathrm{e}}^{-\frac{∆\mathrm{G}°}{\mathrm{RT}}}$

The yield of the product in the reaction

${\mathrm{A}}_2\left(\mathrm{g}\right) + 2\mathrm{B}\left(\mathrm{g}\right) \rightleftharpoons \mathrm{C}\left(\mathrm{g}\right) + \mathrm{Q} \mathrm{kJ} \mathrm{would} \mathrm{be} \mathrm{higher} \mathrm{at}$

• high temperature and high pressure

• high temperature and low pressure

• low temperature and high pressure

• low temperature and low pressure

In which of the following case, does the reaction go farthest to completion?

• K= 10²

• K = 10

• K = 10^-2

• K = 1

The radius of Na⁺ is 95 pm and that of Cl^- ion is 181 pm. Hence, the coordination number of Na⁺ will be

• 4

• 6

• 8

• unpredictable

Mg is an important component of which biomolecule occurring extensively in living world?

• Haemoglobin

• Chlorophyll

• Florigen

• ATP

The correct formula of the complex tetraammineaquachlorocobalt (III) chloride is

• [Cl(H₂O)(NH₃)₄Co]Cl

• [CoCl(H₂O)(NH₃)₄]Cl

• [Co(NH₃)₄(H₂O)Cl]Cl

• [CoCl(H₂O)(NH₃)₄]Cl₂