ECAT Pre Engineering Chemistry Chapter 6 MCQ Test With Answer

Which of the following molecules has unpaired electrons in anti-bonding molecular orbitals?

• O₂ A
• N₂ B
• Br₂ C
• F₂ D

Mg becomes isoelectronic with neon when it

• Loses two electrons A
• Gains two electrons B
• Loses 1 electron C
• Gains 1 electron D

Shape of CIO₃is

• Triangular pyramidal A
• Tetrahedral B
• Triangular planar C
• Triangular bipyramidal D

The electronegativeities of F,Cl,Br and I are 4.0,3.0,2.8,2.5 respectively.Hydrogen halide with a high percentage of ionic character is

• HF A
• HCL B
• HBr C
• HI D

The degree of polarity of molecule is known as its

• Dipole moment A
• Moment arm B
• Bond energy C
• Ionic character D

The boiling point of heavy water is

• 108°C A
• 101.4°C B
• 99°C C
• 110°C D

Atoms obey octet rule by sharing-electrons making covalent bonds according to

• Lewis and Kossal theory A
• Valance bond theory B
• VSEPR theory C
• Molecular orbital theory D

The overlapping of two partially filled atomic orbital is in such a way that the probability of finding the electron pair is maximum along the axis joining the two nuclei, the bond is

• Sigma bond A
• Pi bond B
• Ionic bond C
• Non-polar bond D

The bond angle H - O - H in ice ins closest to

• 120° , 28^' A
• 60° B
• 90° C
• 109° D

During the formation of a chemical bond the potential energy of the system

• Decreases A
• Increases B
• Does not change C
• None of these D

Elements have the tendency to attain 8 electrons in their valence shell. This is known as

• Octer rule A
• Hunds rule B
• Pauli exclusion principle C
• Auf ban principle D

The atomic radius of hydrogen is 37

• Pecometer A
• Manometer B
• Angstrom C
• Micrometer D

In H₂O molecule the bond angle is

• 90° A
• 109.5° B
• 107° C
• 104.5° D

Coordinate covalent bond is present in the molecules

• H₂O A
• BF₃ B
• SiO₂ C
• SO₂ D

Which of the following is a polar molecules

• Carbon dioxide A
• Carbon tetrachloride B
• Methanol C
• Ethane D

The Electro-negatively difference for ionic bond must be greater than

• 1.6 A
• 1.7 B
• 1.8 C
• 1.0 D

Which of the following has unchanged valency?

• H A
• Na B
• Fe C
• Oxygen D

Water H₂O is liquid while hydrogen sulphide H₂S is a gas beause

• Water has higher molecular weight A
• Hydrogen sulphide is a weak acid B
• Sulphure has high electronegativity than oxyhe C
• Water molecules associate through hydrogen bonding D

Maximum hydrogen bonds in water are

• 4 A
• 3 B
• 2 C
• 8 D

A molecule in which sp²hybrid orbitals are used by the central atom in forming covalent bonds in

• He₂ A
• SO₂ B
• PCl₅ C
• N₂ D

Molecular orbital picture of N₂ indicates

• One unpaired electron A
• Two unpaired electron B
• No unpaired electron C
• None of these D

Which of the following molecules have multiple bonds

• CH₄ A
• C₂H₄ B
• C₂H₆ C
• CCI₄ D

The covalent bonds are

• Unidirectional A
• Bi-directional B
• Non-directional C
• Multi-directional D

Among the alkaline earth metals the element forming predominantly covalent compounds is

• Be A
• Mg B
• Sr C
• calcium D

Which carbon is more electronegative?

• sp³- hybridized carbon A
• sp-hybridized carbon B
• sp²-hybridized carbon C
• always same irrespective of its hybrid state D

• Excitantion of an electron from 2s to 2p-orbital A
• Transfer of three electrons from B to the other atoms B
• Excitation of two electrons form 2s orbital to 2p orbital C
• Formation of molecular ion D

H-bonding is not present in

• Glycerine A
• Water B
• Hydrogen sulphide C
• Hydrogen fluride D

All covalent bonds formed between the two atoms are non-polar when

• Covalent bond between two non-metal atoms A
• Covalent bond between metal and non-metal B
• Covalent bond between two atoms of same element C
• Covalent bond between metal atoms D

The electronegativity of elements in a period from left to right

• Decreases A
• Increases B
• First decreases then increases C
• First increases then decreases D

Which of the following charge

• Li A
• Be B
• H C
• He D