Assessment Bengkel PSPM 1 (CHAPTER 4 & 7)

Which is the most plausible Lewis structure for nitrosyl chloride and choose the correct reasoning.

• Structure I because it has zero formal charges on all atoms

• Structure II because it has zero formal charges on all atoms

• Structure I because it has negative formal charge on the more electronegative oxygen atom

• Structure II because it has negative formal charge on the more electronegative oxygen atom

The atoms X and Y have the following electronic configurations: X: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ Y: 1s² 2s² 2p⁴ X and Y are expected to form a compound with a formula

• X²⁺ Y^-

• X²⁺ Y^2-

• (X²⁺)₂ Y^2-

• (X⁺)₂ Y^2-

Predict the shape of ICl₄^- ion

• T-shaped

• Square planar

• Trigonal bipyramidal

• See-saw

Which of the following molecules is non-polar?

• CHCl₃

• XeF₄

• NH₃

• H₂O

What type of hybrid orbital is used for bonding by central atom in SF4?

• sp²

• sp³

• sp³d

• sp³d²

The boiling points of hydrogen chloride and hydrogen bromide are -85 ⁰C and -66 ⁰C. What is the reason in the difference in boiling points?

• Hydrogen chloride molecules are smaller than hydrogen bromide molecules.

• Hydrogen bond exist between hydrogen chloride molecules

• Hydrogen bond exist between hydrogen bromide molecules

• The H-Cl bond is weaker than the H-Br bond.

Which element, magnesium or aluminium has a higher boiling point? Choose the correct reasoning.

• Magnesium because it has 2 valence electrons while aluminium has 3 valence electrons.

• Aluminium because it has stronger metallic bond than magnesium.

• Magnesium because it has stronger metallic bond than aluminium.

• Aluminium because it has larger atomic size than magnesium.

Calculate the pH of 0.01 mol dm^-3 ethanoic acid, CH₃COOH. Given the K_a of ethanoic acid = 1.75 x 10^-5

• 3.72

• 3.52

• 3.32

• 3.92

Calculate the pH of 0.1 mol dm^-3 Ca(OH)₂.

• 13.7

• 13.3

• 12.9

• 12.7

A mixture containing 0.15 mol dm^-3 ethanoic acid and 0.6 mol dm^-3 sodium ethanoate has a pH of 5.35. Calculate the acid dissociation constant of ethanoic acid.

• 1.81 X 10-5

• 1.72 X 10-5

• 1.75 X 10-5

• 1.79 X 10-5