Chapter 4

Assuming \(2 s-2 p\) mixing is NOT operative, the paramagnetic species among the following is [Adv. 2014] (a) \(\mathrm{Be}_{2}\) (b) \(\mathrm{B}_{2}\) (c) \(\mathrm{C}_{2}\) (d) \(\mathrm{N}_{2}\)

Which of the following is soluble in water (a) \(\mathrm{CS}_{2}\) (b) \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\) (c) \(\mathrm{CCl}_{4}\) (d) \(\mathrm{CHCl}_{3}\)

The correct order of hybridization of the central atom in the following species \(\mathrm{NH}_{3},\left[\mathrm{PtCl}_{4}\right]^{2-}, \mathrm{PCl}_{5}\) and \(\mathrm{BCl}_{3}\) is (a) \(d s p^{2}, d s p^{3}, s p^{2}, s p^{3}\) (b) \(s p^{3}, d s p^{2}, s p^{3} d, s p^{2}\) (c) \(d s p^{2}, s p^{2}, s p^{3}, d s p^{3}\) (d) \(d s p^{2}, s p^{3}, s p^{2}, d s p^{3}\)

In which of the following pairs of molecules/ions, both the species are not likely to exist? [Main 2013] (a) \(\mathrm{H}_{2}^{+}, \mathrm{He}_{2}^{2-}\) (b) \(\mathrm{H}_{2}^{-}, \mathrm{He}_{2}^{2-}\) (c) \(\mathrm{H}_{2}^{2+}, \mathrm{He}_{2}\) (d) \(\mathrm{H}_{2}^{-}, \mathrm{He}_{2}^{2+}\)

The total number of electrons that take part in forming the bond in \(\mathrm{N}_{2}\) is [1980] (a) 2 (b) 4 (c) 6 (d) 10

The hybridisation of atomic orbitals of nitrogen in \(\mathrm{NO}_{2}^{+}, \mathrm{NO}_{3}^{-}\)and \(\mathrm{NH}_{4}^{+}\)are (a) \(s p, s p^{3}\) and \(s p^{2}\) respectively (b) \(s p, s p^{2}\) and \(s p^{3}\) respectively (c) \(s p^{2}, s p\) and \(s p^{3}\) respectively (d) \(s p^{2}, s p^{3}\) and \(s p\) respectively

Which one of the following molecules is expected to exhibit diamagnetic behaviour? [Main 2013] (a) \(\mathrm{C}_{2}\) (b) \(\mathrm{N}_{2}\) (c) \(\mathrm{O}_{2}\) (d) \(\mathrm{S}_{2}\)

Which of the following compounds are covalent? (a) \(\mathrm{H}_{2}\) (b) \(\mathrm{CaO}\) (c) \(\mathrm{KCl}\) (d) \(\mathrm{Na}_{2} \mathrm{~S}\)

Molecular shapes of \(\mathrm{SF}_{4}, \mathrm{CF}_{4}\) and \(\mathrm{XeF}_{4}\) are (a) the same, with 2,0 and 1 lone pairs of electrons respectively (b) the same, with 1,1 and 1 lone pairs of electrons respectively (c) different, with 0,1 and 2 lone pairs of electrons respectively (d) different, with 1,0 and 2 lone pairs of electrons respectively

Which of the following is the wrong statement (a) ONCl and \(\mathrm{ONO}^{-}\)are not isoelectronic. (b) \(\mathrm{O}_{3}\) molecule is bent (c) Ozone is violet-black in solid state (d) Ozone is diamagnetic gas.

Element \(X\) is strongly electropositive and element \(Y\) is strongly electronegative. Both are univalent. The compound formed would be [1980] (a) \(X^{+} Y^{-}\) (b) \(X^{-} X^{+}\) (c) \(X-Y\) (d) \(\quad X \rightarrow Y\)

The geometry and the type of hybrid orbital present about the central atom in \(\mathrm{BF}_{3}\) is (a) linear, \(s p\) (b) trigonal planar, \(s p^{2}\) (c) tetrahedral, \(s p^{3}\) (d) pyramidal, \(s p^{3}\).

The octet rule is not valid for the molecule (a) \(\mathrm{CO}_{2}\) (b) \(\mathrm{H}_{2} \mathrm{O}\) (c) \(\mathrm{O}_{2}\) (d) \(\mathrm{CO}\)

Which one of the following compounds has \(s p^{2}\) hydridization? (a) \(\mathrm{CO}_{2}\) (b) \(\mathrm{SO}_{2}\) (c) \(\mathrm{N}_{2} \mathrm{O}\) (d) \(\mathrm{CO}\)

Bond order normally gives idea of stability of a molecular species. All the molecules viz. \(\mathrm{H}_{2}, \mathrm{Li}_{2}\) and \(\mathrm{B}_{2}\) have the same bond order yet they are not equally stable. Their stability order is [Main Online April 22, 2013] (a) \(\mathrm{H}_{2}>\mathrm{B}_{2}>\mathrm{Li}_{2}\) (b) \(\mathrm{Li}_{2}>\mathrm{H}_{2}>\mathrm{B}_{2}\) (c) \(\mathrm{Li}_{2}>\mathrm{B}_{2}>\mathrm{H}_{2}\) (d) \(\mathrm{B}_{2}>\mathrm{H}_{2}>\mathrm{Li}_{2}\)

The compound which contains both ionic and covalent bonds is (a) \(\mathrm{CH}_{4}\) (b) \(\mathrm{H}_{2}\) (c) \(\mathrm{KCN}\) (d) \(\mathrm{KCl}\)

Among the following species, identify the isostructural pairs. \(\mathrm{NF}_{3}\), \(\mathrm{NO}_{3}^{-}, \mathrm{BF}_{3}, \mathrm{H}_{3} \mathrm{O}^{+}, \mathrm{HN}_{3}\) (a) \(\left[\mathrm{NF}_{3}, \mathrm{NO}_{3}^{-}\right]\)and \(\left[\mathrm{BF}_{3}, \mathrm{H}_{3} \mathrm{O}^{+}\right]\) (b) \(\left[\mathrm{NF}_{3}, \mathrm{HN}_{3}\right]\) and \(\left[\mathrm{NO}_{3}^{-}, \mathrm{BF}_{3}\right]\) (c) \(\left[\mathrm{NF}_{3}, \mathrm{H}_{3} \mathrm{O}^{+}\right]\)and \(\left[\mathrm{NO}_{3}^{-}, \mathrm{BF}_{3}\right]\) (d) \(\left[\mathrm{NF}_{3}, \mathrm{H}_{3} \mathrm{O}^{+}\right]\)and \(\left[\mathrm{HN}_{3}, \mathrm{BF}_{3}\right]\)

In which of the following ionization processes the bond energy has increased and also the magnetic behaviour has changed from paramagnetic to diamagnetic ? [Main Online April 9, 2013] (a) \(\mathrm{NO} \rightarrow \mathrm{NO}^{+}\) (b) \(\mathrm{N}_{2} \rightarrow \mathrm{N}_{2}^{+}\) (c) \(\mathrm{C}_{2} \rightarrow \mathrm{C}_{2}{\underline{\phantom{xx}}}^{+}\) (d) \(\mathrm{O}_{2} \rightarrow \mathrm{O}_{2}^{+}\)

The type of hybrid orbitals used by the chlorine atom in \(\mathrm{ClO}_{2}^{-}\)is (a) \(s p^{3}\) (b) \(s p^{2}\) (c) \(s p\) (d) none of these

Among \(\mathrm{B}_{2} \mathrm{H}_{6}, \mathrm{~B}_{3} \mathrm{~N}_{3} \mathrm{H}_{6}, \mathrm{~N}_{2} \mathrm{O}, \mathrm{N}_{2} \mathrm{O}_{4}, \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}, \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{8}\), the total number of molecules containing covalent bond between two atoms of the same kind is

The compound in which \({ }_{\mathrm{C}}^{*}\) uses its \(s p^{3}\) hybrid orbitals for bond formation is : (a) \(\mathrm{H}_{\mathrm{C}}^{*} \mathrm{OOH}\) (b) \(\left(\mathrm{H}_{2} \mathrm{~N}\right)_{2}{\underline{\phantom{xx}}}^{*} \mathrm{C}^{*}\) (c) \(\left(\mathrm{CH}_{3}\right)_{3}{\underline{\phantom{xx}}}^{*} \mathrm{C} \mathrm{OH}\) (d) \(\mathrm{CH}_{3}{\underline{\phantom{xx}}}^{*} \mathrm{C}^{*} \mathrm{HO}\)

The species having bond order different from that in \(\mathrm{CO}\) is (a) \(\mathrm{NO}^{-}\) (b) \(\mathrm{NO}^{+}\) (c) \(\mathrm{CN}^{-}\) (d) \(\mathrm{N}_{2}\)

The species in which the central atom uses \(s p^{2}\) hybrid orbitals in its bonding is (a) \(\mathrm{PH}_{3}\) (b) \(\mathrm{NH}_{3}\) (c) \(\mathrm{CH}_{3}^{+}\) (d) \(\mathrm{SbH}_{3}\)

Among the following, the paramagnetic compound is (a) \(\mathrm{Na}_{2} \mathrm{O}_{2}\) (b) \(\mathrm{O}_{3}\) (c) \(\mathrm{N}_{2} \mathrm{O}\) (d) \(\mathrm{KO}_{2}\)

The two types of bonds present in \(\mathrm{B}_{2} \mathrm{H}_{6}\) are covalent and ..

The hybridisation of sulphur in sulphur dioxide is : (a) \(s p\) (b) \(s p^{3}\) (c) \(s p^{2}\) (d) \(d s p^{2}\)

According to molecular orbital theory which of the following statement about the magnetic character and bond order is correct regarding \(\quad\) [2004S] \(\mathrm{O}_{2}^{+}\) (a) Paramagnetic and Bond order \(<\mathrm{O}_{2}\) (b) Paramagnetic and Bond order \(>\mathrm{O}_{2}\) (c) Diamagnetic and Bond order \(<\mathrm{O}_{2}\) (d) Diamagnetic and Bond order \(>\mathrm{O}\),

The sum of the number of lone pairs of electrons on each central atom in the following species is \(\left[\mathrm{TeBr}_{6}\right]^{2-},\left[\mathrm{BrF}_{2}\right]^{+}, \mathrm{SNF}_{3}\) and \(\left[\mathrm{XeF}_{3}\right]^{-}\) (Atomic numbers: \(\mathrm{N}=7, \mathrm{~F}=9, \mathrm{~S}=16, \mathrm{Br}=35, \mathrm{Te}=52, \mathrm{Xe}=54)\)

Which of the following molecular species has unpaired electron(s)? [2002S] (a) \(\mathrm{N}_{2}\) (b) \(\mathrm{F}_{2}\) (c) \(\mathrm{O}_{2}^{-}\) (d) \(\mathrm{O}_{2}^{2-}\)

Among the triatomic molecules/ions, \(\mathrm{BeCl}_{2}, \mathrm{~N}_{3}^{-}, \mathrm{N}_{2} \mathrm{O}, \mathrm{NO}_{2}^{+}, \mathrm{O}_{3}\),\(\mathrm{SCl}_{2}, \quad \mathrm{ICl}_{2}^{-}, \mathrm{I}_{3}^{-}\)and \(\mathrm{XeF}_{2}\), the total number of linear molecule(s)/ion(s) where the hybridization of the central atom does not have contribution from the \(d\)-orbital(s) is [Atomic number : \(\mathrm{S}=16, \mathrm{Cl}=17, \mathrm{I}=53\) and \(\mathrm{Xe}=54]\)

Identify the least stable ion amongst the following: (a) Li- (b) \(\mathrm{Be}^{-}\) (c) \(\mathrm{B}^{-}\) (d) \(\overline{\mathrm{C}}^{-}\)

A list of species having the formula \(X Z_{4}\) is given below. \(\mathrm{XeF}_{4}, \mathrm{SF}_{4}, \mathrm{SiF}_{4}, \mathrm{BF}_{4}^{-},\mathrm{BrF}_{4}^{-},\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+},\left[\mathrm{FeCl}_{4}\right]^{2-},\left[\mathrm{CoCl}_{4}\right]^{2-}\) and \(\left[\mathrm{PtCl}_{4}\right]^{2-}\) Defining shape on the basis of the location of \(X\) and \(Z\) atoms, the total number of species having a square planar shape is

The common features among the species \(\mathrm{CN}^{-}, \mathrm{CO}\) and \(\mathrm{NO}^{+}\)are [2001S] (a) bond order three and isoelectronic (b) bond order three and weak field ligands (c) bond order two and \(\pi\)-acceptors (d) isoelectronic and weak field ligands

Based on VSEPR theory, the number of 90 degree \(\mathrm{F}-\mathrm{Br}-\mathrm{F}\) angles in \(\mathrm{BrF}_{5}\) is

The correct order of increasing \(\mathrm{C}-\mathrm{O}\) bond length of \(\mathrm{CO}, \mathrm{CO}_{3}^{2-}\), \(\mathrm{CO}_{2}\), is [1999-2 Marks] (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 number and type of bonds between two carbon atoms in \(\mathrm{CaC}_{2}\) are [1996-1 Mark] (a) one sigma \((\sigma)\) and one pi \((\pi)\) bonds (b) one sigma ( \(\sigma\) ) and two pi \((\pi)\) bonds (c) one sigma \((\sigma)\) and one and a half pi \((\pi)\) bonds (d) one sigma ( \(\sigma\) ) bond.

Each of the following options contains a set of four molecules. Identify the option(s) were all four molecules posses permanent dipole moment at room temperature. \(\quad\) [Adv. 2019] (a) \(\mathrm{BF}_{3}, \mathrm{O}_{3}, \mathrm{SF}_{6}, \mathrm{XeF}_{6}\) (b) \(\mathrm{NO}_{2}, \mathrm{NH}_{3}, \mathrm{POCl}_{3}, \mathrm{CH}_{3} \mathrm{Cl}\) (c) \(\mathrm{SO}_{2}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{Cl}, \mathrm{H}_{2} \mathrm{Se}, \mathrm{BrF}_{5}\) (d) \(\mathrm{BeCl}_{2}, \mathrm{CO}_{2}, \mathrm{BCl}_{3}, \mathrm{CHCl}_{3}\)

The angle between two covalent bonds is maximum in ................. \(\left(\mathrm{CH}_{4}, \mathrm{H}_{2} \mathrm{O}, \mathrm{CO}_{2}\right)\)

Number of paired electrons in \(\mathrm{O}_{2}\) molecule is: (a) 7 (b) 8 (c) 16 (d) 14

The molecules that will have dipole moment are (a) 2,2 -dimethylpropane (b) trans-2-pentene (c) cis-3-hexene (d) \(2.2 .3,3\)-tetramethylbutane

The maximum possible number of hydrogen bonds a water molecule can form is [1992-1 Mark] (a) 2 (b) 4 (c) 3

Which of the following is paramagnetic? (a) \(\mathrm{O}_{2}^{-}\) (b) \(\mathrm{CN}^{-}\) (c) \(\mathrm{CO}\) (d) \(\mathrm{NO}^{+}\)

$$ \mathrm{SnCl}_{2} \text { is a non-linear molecule. } $$

The molecule which has pyramidal shape is: (a) \(\mathrm{PCl}_{3}\) (b) \(\mathrm{SO}_{3}\) (c) \(\mathrm{CO}_{3}^{2-}\) (d) \(\mathrm{NO}_{3}^{-}\)

The compound(s) with TWO lone pairs of electrons on the central atom is(are (a) \(\mathrm{BrF}_{5}\) (b) \(\mathrm{ClF}_{3}\) (c) \(\mathrm{XeF}_{4}\) (d) \(\mathrm{SF}_{4}\)

The molecule that has linear structure is (a) \(\mathrm{CO}_{2}\) (b) \(\mathrm{NO}_{2}\) (c) \(\mathrm{SO}_{2}\) (d) \(\mathrm{SiO}_{2}\)

Write the Lewis dot structural formula for each of the following. Give, also, the formula of a neutral molecule, which has the same geometry and the same arrangement of the bonding electrons as in each of the following. An example is given below in the case of \(\mathrm{H}_{3} \mathrm{O}^{+}\)

The linear structure is assumed by : (a) \(\mathrm{SnCl}_{2}\) (b) \(\mathrm{NCO}^{-}\) (c) \(\mathrm{CS}_{2}\) (d) \(\mathrm{NO}_{2}^{+}\)

Hydrogen bonding is maximum in (a) Ethanol (b) Diethyl ether (c) Ethyl chloride (d) Triethylamine

$$ \mathrm{CO}_{2} \text { is isostructural with : } $$ (a) \(\mathrm{HgCl}_{2}\) (b) \(\mathrm{SnCl}_{2}\) (c) \(\mathrm{C}_{2} \mathrm{H}_{2}\) (d) \(\mathrm{NO}_{2}\)