| List I (Anion) | List II (gas evolved on reaction with dil \(H_2SO_4\)) | ||
|---|---|---|---|
| A. | \(CO_3^{ 2−}\) | I. | Colourless gas which turns lead acetate paper black. | 
| B. | \(S^{2–}\) | II. | Colourless gas which turns acidified potassium dichromate solution green | 
| C. | \(SO_3^{ 2−}\) | III. | Brown fumes which turns acidified KI solution containing starch blue. | 
| D. | \(NO_2^{−}\) | IV. | Colourless gas evolved with brisk effervescence, which turns lime water milky. | 

\(CO_3^{ 2−}\): On action of diluted sulphuric acid, \(CO_2\) gas is released which turns lime water milky.
\(S ^{2-}:\) On action of diluted sulphuric acid, \(H_2S\) gas is released which turns lead acetate paper black.
\(SO_3^{ 2−}\): On action of diluted \( H_2SO_4, SO_2\) gas is evolved which turns acidified potassium dichromate solution green.
\(NO^{2−}\): On action of dil \(H_2SO_4, NO_2\) gas is evolved which turns Kl solution contain starch blue.
\(Hence,\) the correct option is (D): \(A-IV, B-I, C-II, D-III\)
The molar conductance of an infinitely dilute solution of ammonium chloride was found to be 185 S cm$^{-1}$ mol$^{-1}$ and the ionic conductance of hydroxyl and chloride ions are 170 and 70 S cm$^{-1}$ mol$^{-1}$, respectively. If molar conductance of 0.02 M solution of ammonium hydroxide is 85.5 S cm$^{-1}$ mol$^{-1}$, its degree of dissociation is given by x $\times$ 10$^{-1}$. The value of x is ______. (Nearest integer)
x mg of Mg(OH)$_2$ (molar mass = 58) is required to be dissolved in 1.0 L of water to produce a pH of 10.0 at 298 K. The value of x is ____ mg. (Nearest integer) (Given: Mg(OH)$_2$ is assumed to dissociate completely in H$_2$O)
Sea water, which can be considered as a 6 molar (6 M) solution of NaCl, has a density of 2 g mL$^{-1}$. The concentration of dissolved oxygen (O$_2$) in sea water is 5.8 ppm. Then the concentration of dissolved oxygen (O$_2$) in sea water, in x $\times$ 10$^{-4}$ m. x = _______. (Nearest integer)
Given: Molar mass of NaCl is 58.5 g mol$^{-1}$Molar mass of O$_2$ is 32 g mol$^{-1}$.
The gas laws were developed at the end of the 18th century, when scientists began to realize that relationships between pressure, volume and temperature of a sample of gas could be obtained which would hold to approximation for all gases.