AIIMS 2018

A solid has a structure in which W atoms are
located at the corners of a cubic lattice.
O atoms at the centre of edges and Na atom
at centre of the cube. The formula for the
compound is

Assertion (A) Graphite is an example of tetragonal crystal system.
Reason (R) For a tetragonal system, \(a=b \neq c\) and \(\alpha=\beta=90^{\circ}, \gamma=120^{\circ}\).

Benzoic acid undergoes dimerisation in benzene solution. The van't Hoff factor \((i)\) is related to the degree of association '\(x\)' of the acid as

The correct order of decreasing stability of
the following carbocation is

The correct IUPAC name of the given compound is

The work function of a metal is \(4.2 \mathrm{~eV}\). If radiation of 2000 \(\mathop A\limits^o\) fall on the metal then the kinetic energy of the fastest photoelectron is

When an excess and a very dilute aqueous
solution of KI is added to very dilute
aqueous solution of silver nitrate. The
colloidal particles of silver iodide which are
associated with the Helmholtz double layer
in the form of

Assertion (A) Micelles are formed by
surfactant molecules above the critical
micellar concentration (CMC).
Reason (R) The conductivity of a solution
having surfactant molecules decreases
sharply at the CMC.

In an adiabatic process, no transfer of heat
takes place between system and
surroundings. Choose the correct option for
free expansion of an ideal gas under
adiabatic condition from the following

\(\Delta H\) and \(\Delta E\) for the reaction,
\(\mathrm{Fe}_2 \mathrm{O}_3(s)+3 \mathrm{H}_2(g) \longrightarrow 2 \mathrm{Fe}(s)+\mathrm{H}_2 \mathrm{O}(l)\)
at constant temperature are related as