List of practice Questions

For a first-order reaction, a plot of \( \ln k \) (y-axis) and \( \frac{1}{T} \) (x-axis) gave a straight line with a slope equal to \( -10^4 \) and an intercept equal to 2.303 (on the y-axis). What is the activation energy \( E_a \) (in kJ/mol) of the reaction? (Given \( R = 8.314 \, \text{J mol}^{-1} \text{K}^{-1} \))
Adsorption of a gas (A) on an adsorbent follows Freundlich adsorption isotherm. The slope and intercept (on y-axis) of the isotherm are 0.5 and 1.0, respectively. What is the value of \( \frac{x}{m} \), when the pressure of the gas (A) is 100 atm?
A low boiling point metal contains high boiling point metal as impurity. The correct refining method is
Identify the element for which \( +1 \) oxidation state is more stable than \( +3 \) oxidation state.
Observe the oxides \( CO, B_2O_3, SiO_2, CO_2, Al_2O_3, PbO_2, Tl_2O_3 \). The number of acidic oxides in the list is:
The common components of photochemical smog are:
The number of activating and deactivating groups of the following are respectively: \[ -OCH_2CH_3, -COCH_3, -NHCOCH_3, -COOCH_3, -SO_3H \]
Consider the following pairs: (A) NO\(_2\) \(>\) O\(_3\) \(>\) H\(_2\)O (Bond angle)
(B) HF \(>\) H\(_2\)O \(>\) NH\(_3\) (Dipole moment)
(C) I\(_2\) \(>\) F\(_2\) \(>\) N\(_2\) (Bond length) Which of the above pairs are correctly matched?
The standard enthalpy of formation (\(\Delta H_f^\circ\)) of ammonia is -46.2 kJ/mol. What is the \(\Delta H_f^\circ\) of the following reaction? \[ N_2(g) + 3H_2(g) \rightarrow 2NH_3(g) \]
Observe the following reactions: \[ \text{I. } H_2O(l) + 2Na(s) \rightarrow 2NaOH(aq) + H_2(g) \] \[ \text{II. } 2H_2O(l) + 2F_2(g) \rightarrow 4H^+(aq) + 4F^-(aq) + O_2(g) \] Identify the correct statement:
What is the correct stability order of \( KO_2, RbO_2, CsO_2 \)?
The heights of the transmitting and receiving antennas are 33.8 m and 64.8 m respectively. The maximum distance between the antennas for satisfactory communication in line of sight mode is:
(Radius of the earth = 6400 km)
Identify the pair of species having the same energy from the following: (The number given in the bracket corresponds to the principal quantum number (n) in which the electron is present.)
Identify the pair of elements in which the number of s-electrons to p-electrons ratio is 2:3:
In a series LCR circuit, if the current leads the source voltage, then:
If the amplitude of the magnetic field part of a harmonic electromagnetic wave in vacuum is \( 270 \) nT, the amplitude of the electric field part of the wave is:
At room temperature, gaseous hydrogen is bombarded with a beam of electrons of 13.6 eV energy. The series to which the emitted spectral line belongs to:
The half-life of a radioactive substance is 12 minutes. The time gap between 28\% decay and 82\% decay of the radioactive substance is:
An element consists of a mixture of three isotopes A, B, and C of masses \( m_1 \), \( m_2 \), and \( m_3 \) respectively. If the relative abundances of the three isotopes A, B, and C is in the ratio 2:3:5, the average mass of the element is:
The concentration of electrons in an intrinsic semiconductor is \( 6 \times 10^{15} \, m^{-3} \). On doping with an impurity, the electron concentration increases to \( 4 \times 10^{22} \, m^{-3} \). In thermal equilibrium, the concentration of the holes in the doped semiconductor is:
A particle of charge \( 2 C \) is moving with a velocity \( (3\hat{i} + 4\hat{j}) \) m/s in the presence of magnetic and electric fields. If the magnetic field is \( ( \hat{i} + 2\hat{j} + 3\hat{k} ) \) T and the electric field is \( (-2\hat{k}) \) NC\(^{-1}\), then the Lorentz force on the particle is:
A rectangular coil of 400 turns and \(10^{-2} \, \text{m}^2\) area, carrying a current of 0.5 A is placed in a uniform magnetic field of 1 T such that the plane of the coil makes an angle of 60° with the direction of the magnetic field. The initial moment of force acting on the coil in Nm is:
The most exotic diamagnetic materials are:
Two circular coils of radii \(r_1\) and \(r_2\) (\(r_1 \ll r_2\)) are placed coaxially with their centers coinciding. The mutual inductance of the arrangement is:
The efficiency of a reversible heat engine working between two temperatures is 50\%. The coefficient of performance of a refrigerator working between the same two temperatures but in reverse direction is: