List of practice Questions

2 moles of ammonia gas is present in a 5.0 L flask at \(27^\circ C\). The pressure of it (in atm) using van der Waals equation is: \[ a=4.17,\qquad b=0.0371,\qquad R=0.0821 \]

At 298 K for reaction \(X \rightleftharpoons Y\), if \(\Delta H^\circ=28.4\;kJ\) and equilibrium constant is \(10^{-7}\), then the standard entropy change for the reaction is:

8 g of NaOH is dissolved in 1.0 L solution containing one mole of acetic acid and one mole of sodium acetate. The pH value of the resulting solution is: \[ pK_a=4.74 \]

Electrolysis of 50% \(H_2SO_4\) solution at high current density gives a compound 'A'. Hydrolysis of 'A' gives 'B'. The number of moles of \(O_2\) produced when 5 moles of 'B' reacts with acidified \(KMnO_4\) solution is:

In the unbalanced reactions given below, the oxidation numbers of oxygen in X, Z and Y are respectively: \[ Li+O_2 \rightarrow X \] \[ Na+O_2(\text{excess}) \rightarrow Z \] \[ K+O_2(\text{excess}) \rightarrow Y \]

If the radius of orbit \(x\) of \(\mathrm{He}^{+}\) (\(Z=2\)) is \(238.05\,\text{pm}\), then the energy of the same orbit (in kJ) is:

In dipositive zinc ion, the number of electrons with \(l=1,\;m=0\) is \(x\), and the number of electrons with \(l=2,\;m=-1\) is \(y\). The sum \(x+y\) is equal to:

Identify the option in which elements are correctly arranged in the increasing order of their electronegativity values.

Identify the correct sets of inner transition elements. \[ \text{I. } \mathrm{Nb,\ W,\ Sg} \] \[ \text{II. } \mathrm{Hs,\ Mt,\ Ds} \] \[ \text{III. } \mathrm{Tb,\ Dy,\ Cf} \] \[ \text{IV. } \mathrm{Nd,\ Bk,\ Es} \] The correct answer is (only):

In which of the following sets, the central atom of both the molecules does not obey the octet rule? \[ \text{I. } \mathrm{SF_4,\ XeF_4} \] \[ \text{II. } \mathrm{SCl_2,\ H_2S} \] \[ \text{III. } \mathrm{SnCl_2,\ XeO_3} \] The correct answer is (only):

The ratio of number of bonding electrons to antibonding electrons in \(O_2^+\) is:

If the speed of the electron in an orbit of hydrogen atom is \(\frac{1}{548}\) times the speed of light in vacuum, then the angular momentum of the electron in this orbit is (h - Planck's constant):

If \(E\) is the kinetic energy of the alpha particle emitted in the decay of a radioactive nucleus of mass number \(A\), then the disintegration energy released in the process is (Parent nucleus is at rest):

The correct statement regarding neutrino is:

In the given circuit, if the forward biased resistance of each diode is \(20\,\Omega\) and the reverse biased resistance of each diode is infinity, then the value of current \(I\) is:

In common emitter configuration of a transistor, if the change in collector current is \(99.5\%\) of the change in emitter current, then the common emitter current amplification factor is:

The combination of a receiver and a transmitter in electronic communication systems is:

A cyclotron with dees of radius \(50\text{ cm}\) and magnetic field \(1.5\text{ T}\) is used to accelerate protons and alpha particles separately. The ratio of the maximum kinetic energies acquired by proton and alpha particle is:

A magnet suspended in the horizontal plane makes 24 oscillations per minute at a place A where the dip angle is \(30^\circ\) and \(n\) oscillations per minute at another place B where the dip angle is \(60^\circ\). If the ratio of the horizontal components of earth's magnetic field at places A and B is \(16:9\), then the value of \(n\) is:

The relation between the total magnetic flux linked with a coil of resistance \(48\Omega\) and time is \(\phi=5-24t\). If there is no heat loss and the heat capacity of the coil is \(5\text{ JK}^{-1}\), then the rise in temperature of the coil during \(t=3\text{ s}\) to \(t=5\text{ s}\) is:

A parallel plate capacitor of capacitance \(5\,\mu\text{F}\) is connected to an AC source. If the relation between the potential difference \(V\) (in volt) across the plates of the capacitor and time \(t\) (in second) is \[ V=7\cos(100\pi t), \] then the displacement current between the plates of the capacitor at a time of \(5\,\text{ms}\) is:

In Young's double slit experiment, if the light of wavelength \(6000\AA\) is used, the fringe width is \(\beta\). If \(I\) is the intensity of light at a point on the screen where the path difference becomes \(2000\AA\), then the intensity of light at a point on the screen which is located at a distance of \(\frac{\beta}{6}\) from the central maximum is:

When two electric charges are placed at a distance apart in air, the electrostatic force between them is \(400\text{ N}\). If \(\frac13\) of the space between the two charges is filled with a medium of dielectric constant \(4\), then the electrostatic force between them is:

The electric potentials at two points A and B are \(+60\text{ V}\) and \(-30\text{ V}\) respectively. If a particle of mass \(20\,\mu\text{g}\) and charge \(+10\,\mu\text{C}\) is released from rest at point A, then the velocity with which the particle reaches point B is:

When a current of \(3\text{ A}\) flows through a uniform copper wire of radius \(0.6\text{ mm}\), the average drift speed of the electrons is \(V\). If \(1.5\text{ A}\) current is flowing in another uniform copper wire of radius \(1.2\text{ mm}\), then the average drift speed of the electrons is: