Chemistry Test ...

Which of the following methods is suitable for preventing an iron frying pan from rusting?

The basic unit of nucleic acid is ___________.

Exactly \(1 {~g}\) of urea dissolved in \(75 {~g}\) of water gives a solution that boils at \(100.114^{\circ} {C}\) at 760 torr. The molecular weight of urea is \(60.1\). The boiling point elevation constant for water is:

The stepwise formation of \(\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)_4\right]^{2+}\) is given below

\(\mathrm{Cu}^{2+}+\mathrm{NH}_3 \stackrel{\mathrm{K}_1}{\rightleftharpoons}\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)_2\right]^{2+} \)

\( {\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)^{2+}+\mathrm{NH}_3 \stackrel{\mathrm{K}_2}{\rightleftharpoons}\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)_2\right]^{2+}\right.} \)

\({\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)_2\right]^{2+}+\mathrm{NH}_3 \stackrel{\mathrm{K}_3}{\rightleftharpoons}\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)_3\right]^{2+}} \)

\({\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)_3\right]^{2+}+\mathrm{NH}_3 \stackrel{\mathrm{K}_4}{\rightleftharpoons}\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)_4\right]^{2+}}\)

The value of stability constants \(\mathrm{K}_1, \mathrm{~K}_2, \mathrm{~K}_3\) and \(\mathrm{K}_4\) are \(10^4, 1.58 \times 10^3, 5 \times 10^2\) and \(10^2\) respectively. The overall equilibrium constants for dissociation of \(\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)_4\right]^{2+}\) is \(\mathrm{x} \times 10^{-12}\). The value of \(\mathrm{x}\) is________(Rounded off to the nearest integer)

Which of the statements about the reaction below are incorrect?

\(2 P b O(s)+C(s) \rightarrow 2 P b(s)+C O_{2}(g)\)

(a) Lead is getting reduced.

(b) Carbon dioxide is getting oxidised.

(c) Carbon is getting oxidised.

(d) Lead oxide is getting reduced.

Among the lanthanides, the one obtained by synthetic method is:

An aqueous solution containing \(0.25\) moles of non-volatile but strong electrolytes solute \(X\) in \(500 \mathrm{~g}\) water freeze at \(-2.79^{0} \mathrm{C}\). The number of ions furnished in water per formula unit of \({X}\) is \(\left(K_{f}=\right.\) \(1.86\) )

The increasing order of the first ionisation enthalpies of the elements B, P, S and \(\mathrm{F}\) (lowest first) is:

The complex \(\left[ Co \left( NH _{3}\right)_{5}\left( NO _{2}\right)\right]^{2+}\) and \(\left[ Co \left( NH _{3}\right)_{5}( ONO )\right]^{2+}\) are called:

Ionic species are stabilised by the dispersal of charge, which of the following carboxylate ions is the most positive charge?