List of practice Questions

Identify the set of acidic oxides.

Identify $Z$ in the following sequence of reactions. $\ce{ C_2 H_4 Br_2 ->[(i) Alc.KOH][(ii) NaNH_2] X ->[Red\, hot][Fe \,tube\, 873 K] Y ->[(CH_3CO)_2 O/\Delta][Anhyd. AlCl_3] Z}$

If only $\frac{1}{51}^{th}$ ot the main current is to be passed through a galvanometer then the shunt required is $R_1$ and if only $\frac{1}{11}^{th}$ of the main voltage is to be developed across the galvanometer, then the resistance required is $R_2$. Then $\frac{R_2}{R_1} =$

In the first order thermal decomposition of $C _{2} H _{5} I (g) \longrightarrow C _{2} H _{4}(g)+ HI (g)$, the reactant in the beginning exerts a pressure of $2$ bar in a closed vessel at $600 \,K$. If the partial pressure of the reactant is $0.1$ bar after $1000$ minutes at the same temperature the rate constant in $\min ^{-1}$ is $(\log 2=0.3010)$

In a nuclear reactor the activity of a radioactive substance is $2000 / s$. If the mean life of the products is $50$ minutes, then in the steady power generation, the number of radio nuclides is

In a $p$ - type semiconductor the donor level is at $50 \,meV$ above the valence band. To produce one electron, the maximum wavelength of light photon required is (Planck's constant, $h=6.6 \times 10^{-34} \,Js$ and speed of light in vacuum, $c=3 \times 10^{8} \,ms ^{-1}$ )

Potential energy of a body of mass $1\, kg$ free to move along X-axis is given by $U(x) = \left( \frac{x^2}{2} - x \right) J .$ If the total mechanical energy of the body is $2\, J$. then the maximum speed of the body is (Assume only conservative force acts on the body)

Sodium nitrite is reacted with $H_2SO_4$ to form $NaHSO_4, HNO_3$, water and $X$. Gold is dissolved in aqua-regia to form water, $AuCl^{-}_4$ and $Y. X$ and $Y$ are respectively

The average translational kinetic energy of a molecule in a gas becomes equal to $0.69\, eV$ at a temperature about [Boltzmann constant = $1.38 \times 10^{-23} \; J \; K^{-1}$]

The copper (II) halide which does not exist is

The electric field intensity at a point on the axis of an electric dipole in ah is $4 \; NC^{-1}$. Then the electric field intensity at a point on the equitorial hue which is at a distance equal to twice the distance on the axial line and if the dipole is in a medium of dielectric constant $4$ is

The non-biodegradable waste formed in fertilizer industries is

The number of moles of solute present in the solutions of $I, II$ and $III$ is respectively I. $500 \,mL$ of $0.2\, M\, NaOH$ II. $200 \,mL$ of $0.1 \,N \,H _{2} SO _{4}$ II. $6 g$ of urea in $1 \,kg$ of water

The pair of metals refined by "vapour phase refining" is

The velocity of an object moving in a straight line path is given as a function of time by $v = 6t - 3t^2$. where $v$ is in $ms^{-1} , t $ is in $s$. The average velocity of the object between $t = 0$ and $t = 2s$ is

The wave functions of $1s$ orbitals of two hydrogen atoms are $\Psi_A$ and $\Psi_B$. $\Psi_A$ and $\Psi_B$ are linearly combined to form two molecular orbitals ($\sigma$ and $\sigma^{\ast}$). Which of the following statements are collect? I. $\sigma^{*}$ is equal to $(\Psi_{A}-\Psi_{B})$. II. In $\sigma$ - orbital, one nodal plane is present in between two nuclei. III. The energy of $\sigma$ - orbital is lower than the energy of $\sigma^{*}$ -orbital.

When a hydrogen atom emits a photon during a transition from $n = 4$ to $n = 2$, its recoil speed is about

A rough inclined plane $B C E$ of height $\left(\frac{25}{6}\right)\, m$ is kept on a rectangular wooden block $A B C D$ of height $10 m$, as shown in the figure. A small block is allowed to slide down from the top $E$ of the inclined plane. The coefficient of kinetic friction between the block and the inclined plane is $\frac{1}{8}$ and the angle of inclination of the inclined plane is $\sin ^{-1}(0.6)$. If the small block finally reaches the ground at a point $F$, then $D F$ will be (Acceleration due to gravity, $g =10 \,ms ^{-2}$ )

The speed of a particle changes from $\sqrt{5} \,ms^{- 1}$ to $2 \sqrt{5} \; ms^{-1}$ in a time If the magnitude of change in its velocity is $5 \; ms^{-1}$, the angle between the initial and final velocities of the particle is

Two small spheres of each charge $q$, mass $m$ and material density $d$ are suspended from a fixed point with the help of inextensible light thread. When the spheres are in air, the angle between the threads is $90^{\circ}$. When the spheres are suspended in a liquid of density $\frac{2}{2} d$, the angle between the threads is $60^{\circ}$. The $3$ value of dielectric constant of the liquid is

An $\alpha$-particle moves in a circular path of radius $1\, cm$ in a uniform magnetic field of $0.125\, T$. The de Broglie wavelength associated with the $\alpha$-particle is

Which of the following are carbonate ores? l) Magnetite II) Kaolinite III) Siderite IV) Calamine

White phosphorus is heated with concentrated $NaOH$ in $CO _{2}$ atmosphere to form a gas $A$ and compound $B$. When $A$ is bubbled into aqueous $CuSO _{4}$ solution copper phosphide and $C$ are formed, $B$ and $C$ are respectively

Which one of the following has maximum number of hybrid orbitals ?

Which of the following metals exist in liquid state duiing summer season?