The standard electrode potential $$\mathrm{(M^{3+}/M^{2+})}$$ for V, Cr, Mn & Co are $$-$$0.26 V, $$-$$0.41 V, + 1.57 V and + 1.97 V, respectively. The metal ions which can liberate $$\mathrm{H_2}$$ from a dilute acid are :

Following chromatogram was developed by adsorption of compound 'A' on a 6 cm TLC glass plate. Retardation factor of the compound 'A' is _________ $$\times 10^{-1}$$.

Millimoles of calcium hydroxide required to produce 100 mL of the aqueous solution of pH 12 is $$x\times10^{-1}$$. The value of $$x$$ is ___________ (Nearest integer).

Assume complete dissociation.

For certain chemical reaction $$X\to Y$$, the rate of formation of product is plotted against the time as shown in the figure. The number of $$\mathrm{\underline {correct} }$$ statement/s from the following is ___________.

(A) Over all order of this reaction is one.

(B) Order of this reaction can't be determined.

(C) In region I and III, the reaction is of first and zero order respectively.

(D) In region-II, the reaction is of first order.

(E) In region-II, the order of reaction is in the range of 0.1 to 0.9.