Observe the following solutions
I. Black coffee
II. \(0.2 \mathrm{M} \mathrm{NaOH}\)
III. Lemon juice
IV. Lime water
V. Human Saliva
VI. Tomato juice
The number of solutions with \(\mathrm{pH}\) less than 7 is

The vapour pressures of chloroform $\left({\mathrm{CHCl}}_3\right),$ dichloromethane $\left({\mathrm{CH}}_2{\mathrm{Cl}}_2\right)$ at $298 \mathrm{K}$ are $200 \mathrm{mmHg}$ and $415 \mathrm{mmHg}$, respectively. An ideal solution is prepared by mixing $59.75 \mathrm{g}$ of ${\mathrm{CHCl}}_3$ and $21.25 \mathrm{g}$ of ${\mathrm{CH}}_2{\mathrm{Cl}}_2$, the mole fractions of chloroform and dichloromethane in vapour phase, respectively are

If for the reaction \(\mathrm{CCl}_4(\mathrm{~g}) \rightarrow \mathrm{C}(\mathrm{g})+4 \mathrm{Cl}(\mathrm{g})\) the following data is given
\(\begin{aligned} & \Delta_{\mathrm{vap}} \mathrm{H}^\theta \mathrm{CCl}_4(\mathrm{l})=30 \mathrm{~kJ} \mathrm{~mol}^{-1} \text {, vap = vaporization } \\ & \Delta_{\mathrm{f}} \mathrm{H}^\theta{ }_{\mathrm{CCl}_4}=-136.0 \mathrm{~kJ} \mathrm{~mol}^{-1}, \mathrm{f}=\text { formation } \\ & \Delta_{\mathrm{a}} \mathrm{H}_{\mathrm{C}}^{\mathrm{q}}=714.0 \mathrm{~kJ} \mathrm{~mol}^{-1}, \mathrm{a}=\text { atomization } \\ & \Delta_{\mathrm{a}} \mathrm{H}^\theta \mathrm{Cl}_2=242.0 \mathrm{~kJ} \mathrm{~mol}^{-1}, \mathrm{a}=\text { atomization }\end{aligned}\)
the bond mean enthalpy of \(\mathrm{C}-\mathrm{Cl}\) in \(\mathrm{CCl}_4(\mathrm{l})\) is

Two statements are given below.
Statement I: Nitrogen has more ionization enthalpy and electronegativity than beryllium
Statement II: \(\mathrm{CrO}_3, \mathrm{~B}_2 \mathrm{O}_3\) are acidic oxides
Correct answer is

The chemical reaction that involves roasting process is

A compound is formed by two elements A and B. Atoms of the element B (as anion) make ccp lattice and those of element \(A\) (as cation) occupy all tetrahedral voids. The formula of the compound is

What is the mass of a particle with a wavelength of \(3.313 Å\) moving with a speed of \(2.0 \times 10^8 \mathrm{~ms}^{-1}\) ?

The charge on colloidal particles is due to

The number of metalloids in the following elements are \(\mathrm{Si}, \mathrm{Mn}, \mathrm{B}, \mathrm{F}, \mathrm{Cu}, \mathrm{Ag}, \mathrm{K}, \mathrm{Sb}, \mathrm{As}, \mathrm{Na}, \mathrm{Ge}\)

\(\int_0^\pi \frac{x \tan x}{\sec x+\tan x} d x=\)

A square is inscribed in the circle \(x^2+y^2-2 x+4 y-93=0\) with its sides parallel to the co-ordinate axes. Then which among the following can be one of the vertices of the square?

If the ionic product of \(\mathrm{Ni}(\mathrm{OH})_2\) is \(1.9 \times 10^{-15}\), the molar solubility of \(\mathrm{Ni}(\mathrm{OH})_2\) in \(1.0 \mathrm{M} \mathrm{NaOH}\) is

In Young's double slit experiment, two slits are placed 2 mm from each other. Interference pattern is observed on a screen placed 2 m from the plane of the slits. Then the fringe width for a light of wavelength 400 nm is