Sulphur sodium extract is acidified with acetic acid because lead acetate is soluble and does not interfere with the test.
\(\underset { Leadacetate }{ Pb\left( { OCOCH }_{ 2 } \right) } +{ H }_{ 2 }{ SO }_{ 4 }\longrightarrow { PbSO }_{ 4 }\downarrow +{ 2CH }_{ 3 }COOH\)

The tendency of an atom to form a chain of bonds with the atoms of the same element is called catenation. The high strength of C-C bond is responsible for its catenation property.

Total valence electrons = 4 + 6 x 2 = 16
\({16\over 8}\) = 2(Q₁) + O(R₁)
\(\therefore\) X = 2
\(\therefore\) Hybridisation in CO2 is sp. Hence it is Linear in shape

K_H is a empirical constant with the dimensions of pressure. The value of 'K_H' depends on the nature of the gaseous solute and solvent.

\(\Delta G^{\ominus}\) = -RT In K, thus if \(\Delta G^{\ominus}\) is less than zero i.e., it is negative, then InK will be positive and hence K will be greater than one.

Since group 1 hydroxides and carbonates due to large size contain higher hydration energy than the lattice energy so, they are easily soluble in water. Whereas, in magnesium and calcium due to small size their lattice energy dominates over hydration energy they are sparingly soluble in water.

The pressure decreases with the increase in altitude because there are fewer molecules per unit volume of air. Above 9200 m (30,000 ft), for example, where most commercial aeroplanes fly, the pressure is so low that one could pass out for lack of oxygen. For this reason most aeroplanes cabins are artificially pressurized.

In ice, each oxygen atom is surrounded tetrahedrally by through hydrogen bonds to four water molecules. That is, the presence of two hydrogen atoms and two lone electron pairs (on oxygen) in each water molecule results in a three-dimensional structure. The arrangements creates an open structure, which in turn accounts for the fact that ice is less dense than water at 0⁰C.

Gram equivalent mass of an element, compound or ion is the mass of their species that combines or displaces 1.008g hydrogen or 8g oxy,gen or 35.5g chlorine.

The ionisation energy decreases down a group. Down a group, the valence electron occupies new shells, the distance between the nucleus and the valence electron increases. So, the nucleat forces of attraction on valence electron decreases and hence ionisation energy also decreases. down a group.