Chapter 3

Of the following hydrides, which has the lowest boiling point? (a) \(\mathrm{NH}_{3}\) (b)' \(\mathrm{PH}_{3}\) (c) \(\mathrm{SbH}_{3}\) (d) \(\mathrm{AsH}_{3}\)

The energy of hydrogen atom in its ground state is \(-13.6 \mathrm{eV}\). The energy of the level corresponding to \(n=5\) is: (a) \(-0.54 \mathrm{eV}\) (b) \(-5.40 \mathrm{cV}\) (c) \(-0.85 \mathrm{eV}\) (d) \(-2.71 \mathrm{eV}\)

Non-isostructural pair among the following is (a) \(\mathrm{XeF}_{2}, \mathrm{Br}_{3}^{-}\) (b) \(\mathrm{XeF}_{4}, \mathrm{PF}_{4}^{+}\) (c) \(\mathrm{CO}_{2}, \mathrm{I}_{3}^{-}\) (d) \(\mathrm{MnO}_{4}^{-}, \mathrm{ClO}_{3}^{-}\)

Which hydrogen-like species will have the same radius as that of the Bohr orbit of a hydrogen atom ? (a) \(n=2, \mathrm{Li}^{2+}\) (b) \(n=2, \mathrm{Be}^{3+}\) (c) \(n=2, \mathrm{He}^{+}\) (d) \(n=3, \mathrm{Li}^{2+}\)

Which of the following oxyacids of sulphur contains no sulphur-sulphur (S-S) bonds? (a) \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{4}\) (b) \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{5}\) (e) \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{7}\) (d) \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}\)

If the kinetic energy of an electron is increased four times, the de broglie's wavelength associated with it becomes (a) 4 times (b) 2 times (c) \(1 / 2\) times (d) \(1 / 4\) times

Among \(\mathrm{LiCl}, \mathrm{BeCl}_{2}, \mathrm{NaCl}, \mathrm{CsCl}\), the compounds with the greatest and the least ionic character respectively are (a) LICI and \(\mathrm{CsCl}\) (b), \(\mathrm{NaCl}\) and \(\mathrm{LiCl}\) (c) \(\mathrm{CSC} \mid\) and \(\mathrm{NaCl}\) (d) \(\mathrm{C}_{5} \mathrm{Cl}\) and \(\mathrm{BeCl}_{2}\)

According to Bohr's theory, the angular momentum for an electron of \(5^{\text {th }}\) orbit is : (a) \(5 h / \pi\) (b) \(2.5 h / \pi\) (c) \(5 \pi h\) (d) \(25 h / \pi\)

Which of the following has the least number of unpaired d-electrons? (a) \(\mathrm{Zn}^{2+}\) (b) \(\mathrm{F} \mathrm{e}^{2+}\) (c) \(\mathrm{Ni}^{2+}\) (d) \(\mathrm{Cu}^{2+}\)

Which of the following oxoacids of sulphur contains \(S=S\) bond? (a) \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{6}\) (b) \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}\) (c) \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{8}\) (d) \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{4}\)

The amount of energy needed to excite a hydrogen atom from its ground state to the second excited state is (a) \(12.1 \mathrm{eV}\) (b) \(10.2 \mathrm{eV}\) (c) \(13.6 \mathrm{eV}\) (d) \(34 \mathrm{eV}\)

The shape of \(\mathrm{XeF}_{4}\) is (a) Tetrahedral (b) Square planar (c) Pyramidal (d) Nearly linear

Any p-orbital can accommodate up to: (a) 4 electrons (b) 2 electrons with parallel spins (c) 6 electrons (d) 2 electrons with opposite spins

In an atom two electrons are moving in orbits of radii \(r\) and \(9 r\). The ratio of time taken by them to complete one revolution is (a) \(1: 9\) (b) \(1: 3\) (c) \(1: 27\) (d) \(1: 6\)

The number of electrons in the 3 d shell of the element with atomic number 26 is (a) 4 (b) 6 (c) 8 (d) 10

The structure of \(\mathrm{XeO}_{2} \mathrm{~F}_{2}\) is (a) Plane triangular (b) Trigonal bipyramidal (c) Square planar (d) Tetrahedral

Principal, arimuthal and magnetic quantum numbers are respectively related to: (a) size, shape and orientation (b) shape, size and orientation (d) none of the above (c) sire, orientation and shape (d) none of the above

The bonding of \(\mathrm{S}\) in \(\mathrm{SCl}_{4}\) molecule involves (a) sp orbitals (b) \(\mathrm{sp}^{2}\) orbitals (c) \(sp^{3}\) orbitals (d) \(\mathrm{dsp}^{2}\) orbitals

The correct order of decreasing polarisable ions is (a) \(\mathrm{Cl}^{-}, \mathrm{Br}^{-}, \mathrm{F}, \mathrm{F}^{-}\) (b) \(\mathrm{F}^{-}, \mathrm{I}, \mathrm{Br}^{-}, \mathrm{Cl}^{-}\) (c) \(\mathrm{F}, \mathrm{Cl}^{-}, \mathrm{Br}^{-}, \mathrm{I}^{-}\) (d) \(\mathrm{I}^{-}, \mathrm{Br}^{-}, \mathrm{Cl}^{-}, \mathrm{F}^{-}\)

Different lines in Lyman series of hydrogen spectrum lie in: (a) UV (b) visible (c) \(\mathrm{IR}\) (d) far IR

Among the following, the pair in which the two species are not isostructural is (a) \(\mathrm{IO}_{3}^{-}\)and \(\mathrm{XeO}_{3}\) (b) \(\mathrm{BH}_{4}^{-}\)and \(\mathrm{NH}_{4}^{+}\) (c) \(\mathrm{PF}_{6}^{-}\)and \(\mathrm{SF}_{6}\) (d) \(\mathrm{SiF}_{4}\) and \(\mathrm{SF}_{4}\)

The orbital angular momentum of an electron in 2 s orbital is: (a) \(h / 4 \pi\) (b) Zero (c) \(h / 2 \pi\) (d) \(h / \sqrt{2} \pi\)

Which of the following reactions led to the discovery of the neutron? (a) \({ }_{6}^{14} \mathrm{C}+{ }_{1}^{1} \mathrm{P} \rightarrow{ }_{7}^{14} \mathrm{~N}+{ }_{0}^{1} \mathrm{n}\) (b) \({ }_{5}^{11} \mathrm{~B}+{ }_{1}^{2} \mathrm{D} \rightarrow{ }_{6}^{12} \mathrm{C}+{ }_{0}^{1} \mathrm{n}\) (c) \({ }_{4}^{9} \mathrm{Be}+{ }_{2}^{4} \mathrm{He} \rightarrow{ }_{6}^{12} \mathrm{C}+{ }_{0}^{1} \mathrm{n}\) (d) \(8 \mathrm{Be}+{ }_{2}^{4} \mathrm{He} \rightarrow{ }_{6}^{\prime \prime} \mathrm{C}+{ }_{0}^{1} \mathrm{n}\)

The structure of \(\mathrm{XeF}_{2}\) is (a) square planar (b) tetrahedral (c) octahedral (d) trigonal bipyramidal

A transition metal cation \(\mathrm{M}^{3+}\) has a magnetic moment \(\sqrt{35}\). what is the atomic number of the metal? (a) 24 (b) 25 (c) 26 (d) 27

Which of the following molecules forms 2 -electron 3 -centred bonds? (a) \(\mathrm{Al}_{2} \mathrm{Cl}_{6}\) (b) \(\mathrm{Hg}_{2} \mathrm{Cl}_{2}\) (c) \(\mathrm{B}_{2} \mathrm{H}_{6}\) (d) \(\mathrm{BH}_{3}\)

Number of unpaired electrons in \(\mathrm{Cu}^{2+}\) is: (a) zero (b) 9 (c) 3 (d) 1

The shape of sulphate ion is (a) hexagonal (b) square planar (c) trigonal bipyramidal (d) tetrahedral

The line spectra of two elements are not identical because (a) The elements do not have the same number of neutrons (b) They have different mass numbers (c) Their outermost electrons are at different energy levels (d) They have different valencies

Of the following sets, which does not contain isoelectronic species? (a) \(\mathrm{PO}_{4}^{3}, \mathrm{SO}_{4}^{2}, \mathrm{ClO}_{4}-\) (b) \(\mathrm{CN}^{-}, \mathrm{N}_{2}, \mathrm{C}_{2}^{2-}\) (c) \(\mathrm{SO}_{3}^{2-}, \mathrm{CO}_{3}^{2-}, \mathrm{NO}_{3}^{-}\) (d) \(\mathrm{BO}_{3}^{3}, \mathrm{CO}_{3}^{2-}, \mathrm{NO}_{3}^{-}\)

If spin quantum number could have 3 values instead of 2, where would the last electron enter in the ground state electronic configuration of cobalt? (a) \(3 \mathrm{~d}\) (b) \(3 \mathrm{p}\) (c) \(4 \mathrm{p}\) (d) \(4 \mathrm{~s}\)

The maximum number of \(90^{\circ}\) angles between bond pair-bond pair of electrons is observed in (a) dsp" hybridization (b) \(\mathrm{sp}^{3} \mathrm{~d}^{2}\) hybridization (c) dsp \(^{2}\) hybridization (d) sp"d hybridization

Which particle among the following will have the smallest de Broglie wavelength, assuming that they have the same velocity? (a) A positron (b) A photon (c) An \(\alpha\)-particle (d) A neutron

The hybrid orbital used by chlorine atom in \(\mathrm{ClO}_{2}^{-}\)ion is (a) \(s p^{3}\) (b) \(\mathrm{sp}^{2}\) (c) \(\mathrm{sp}\) (d) none

Calculate the wavelength of spectral line of the longest wavelength in balmer series for hydrogen atom. (a) \(1526 \mathrm{~nm}\) (b) \(124 \mathrm{~nm}\) (c) \(956 \mathrm{~nm}\) (d) \(656 \mathrm{~nm}\)

The enolic form of acetone has (a) 9 sigma bonds, 1 pi bond and 2 lone pairs (b) 8 sigma bonds, 2 pi bonds and 2 lone pairs (c) 10 sigma bonds, 1 Pi bond and 1 lone pair (d) 9 sigma bonds, 2 pi bonds and 1 lone pair

The value of the magnetic moment of a particular ion is \(2.83\) Bohr magneton. The ion is (a) \(\mathrm{Fe}^{2+}\) (b) \(\mathrm{Ni}^{2+}\) (c) \(\mathrm{Mn}^{2+}\) (d) \(\mathrm{Co}^{3+}\)

A subshell with \(l=2\) is called (a) \(\mathrm{s}\) (b) \(\mathrm{p}\) (c) \(\mathrm{d}\) (d) \(\mathrm{f}\)

The correct order of bond angles (smallest first) in \(\mathrm{H}_{2} \mathrm{~S}, \mathrm{NH}_{3}, \mathrm{BF}_{3}\) and \(\mathrm{SiH}_{4}\) is (a) \(\mathrm{H}_{2} \mathrm{~S}<\mathrm{SiH}_{4}<\mathrm{NH}_{3}<\mathrm{BF}_{3}\) (b) \(\mathrm{H}_{2} \mathrm{~S}<\mathrm{NH}_{3}<\mathrm{BF}_{3}<\mathrm{SiH}_{4}\) (c) \(\mathrm{H}_{2} \mathrm{~S}<\mathrm{NH}_{3}<\mathrm{SiH}_{4}<\mathrm{BF}_{3}\) (d) \(\mathrm{NH}_{3}<\mathrm{H}_{2} \mathrm{~S}<\mathrm{SiH}_{4}<\mathrm{BF}_{3}\)

The ratio of radii of \(2^{\text {nd }}, 4^{\text {th }}\) and \(6^{\text {th }}\) orbit of hydrogen atom is: (a) \(2: 4: 6\) (b) \(1: 4: 9\) (c) \(1: 4: 6\) (d) \(1: 2: 3\)

Number of sigma bonds in \(\mathrm{P}_{4} \mathrm{O}_{10}\) is (a) 6 (b) 7 (c) 17 (d) 16

The relative abundance of two rubidium isotopes of atomic weight 85 and 87 are \(75 \%\) and \(25 \%\) respectively. The average atomic weight will be (a) \(75.5\) (b) \(85.5\) (c) \(86.5\) (d) \(87.5\)

The \(\mathrm{H}-\mathrm{O}-\mathrm{H}\) angle in water molecule is (a) \(104.5^{\circ}\) (b) \(107^{\circ}\) (c) \(109.5^{\circ}\) (d) \(100^{\circ}\)

Energy of Bohr's orbit: (a) increases as we move away from the nucleus (b) decreases as we move away from the nucleus (c) remains the same as we move away from the nucleus (d) none of these

Which one of the following pairs of species have the same bond order? (a) \(\mathrm{CN}^{-}\)and \(\mathrm{NO}^{+}\) (b) \(\mathrm{CN}\) and \(\mathrm{CN}^{+}\) (c) \(\mathrm{O}_{2}^{-}\)and \(\mathrm{CN}^{-}\) (d) \(\mathrm{NO}^{+}\)and \(\mathrm{CN}^{+}\)

What possibly can be the ratio of the de Broglie wavelengths for two electrons having the same initial energy and accelerated through \(50 \mathrm{~V}\) and \(200 \mathrm{~V}\) ? (a) \(3: 10\) (b) \(10: 3\) (c) \(1: 2\) (d) \(2: 1\)

The correct order of increasing \(\mathrm{C}-\mathrm{O}\) bond length of \(\mathrm{CO}, \mathrm{CO}_{3}^{2-}, \mathrm{CO}_{2}\) is (a) \(\mathrm{CO}_{3}^{2}<\mathrm{CO}_{2}<\mathrm{CO}\) (b) \(\mathrm{CO}_{2}<\mathrm{CO}_{3}^{2-}<\mathrm{CO}\) (c) \(\mathrm{CO}<\mathrm{CO}_{3}^{2-}<\mathrm{CO}_{2}\) (d) \(\mathrm{CO}<\mathrm{CO}_{2}<\mathrm{CO}_{3}^{2-}\)

The quantum number not obtained from Schrodinger's wave equation is (a) \(\bar{n}\) (b) 1 (c) \(\mathrm{m}\) (d) \(s\)

Correct sequence of increasing covalent character is represented oy (a) \(\mathrm{LiCl}, \mathrm{NaCl}, \mathrm{BeCl}_{2}\) (b) \(\mathrm{BeCl}_{2}, \mathrm{NaCl}, \mathrm{LiCl}\) (c) \(\mathrm{NaCl}, \mathrm{LiCl}, \mathrm{BeCl}_{2}\) (d) \(\mathrm{BeCl}_{2}, \mathrm{LiCl}, \mathrm{NaCl}\)

If the radius of the first Bohr orbit of the \(\mathrm{H}\) atom is \(r\) then for the \(\mathrm{Li}^{2+}\) ion it will be (a) \(3 r\) (b) \(9 r\) (c) \(r / 3\) (d) \(r 9\)