1000 Questions Group VII

Question 1

Define electronegativity and explain the trend down group VII.

Question 2

Draw a chart showing the electronegativities of group VII. Explain the trends shown in the chart.

Question 3

Draw a chart showing the bond enthalpies of the halogen. Explain the trends shown in the chart.

Question 4

Discuss the acidity of the hydrogen halides and explain why some acids are considered to be weak acids whilst other hydrogen halides are considered to be very strong acids.

Question 5

NaBr can be used in the preparation of both HBr and Br₂. Write reactions for these transformations and discuss any differences between the reactions of NaBr and those of NaCl and NaI.

Question 6

Describe a method of preparation of anhydrous AlCl₃. How can this be purified?

Question 7

Describe a method of preparation for FeCl₂ and FeCl₃.

Question 8

Cl₂ reacts differently with cold and hot NaOH. Write equations for the two different sets of conditions.

Question 9

Explain the trends in boiling points for the halogens.

Question 10

Explain the trends in boiling points for the hydrogen halides.

Question 11

An aqueous solution of 0.1M HF is 7.8% dissociated. Calculate K_a for the reaction.

Question 12

A Cl and F compound has the percentage composition 37.4% Cl and 61.6% F. 0.181g of the gaseous compound occupies 46 cm³ at 20^oC and 1 atm. Draw the shape of the compound.

Question 13

Draw the shapes of the following ions:

BrF₃, ClO₂^–, ClO₄^–, IF₅, ICl₂^–

Question 14

Cl₂, Br₂ and I₂ will all oxidise H₂S to S. Cl₂ and Br₂ will oxidise NO₂^– to NO₃^– whilst I₂ will not. Cl₂ will oxidise Br^– to Br₂. Write equations for all reactions and explain which halogen is the strongest oxidising agent.

Question 15

Cl₂ and I₂ have different oxidising powers. Using their reaction with S₂O₃^2- show which is the strongest oxidising agent.

Question 16

F₂ can only form the -1 oxidation state whilst all the other halogens have multiple oxidation states. Explain.

Question 17

Iodine is practically insoluble in water but soluble in CCl₄. Explain.

Question 18

Whilst I₂ is insoluble in water, it will dissolve in a solution of KI. Explain.

Question 19

SiCl₄ can be hydrolysed with water to form SiO₂ and HCl. An unknown volume of liquid SiCl₄ was added to 400 cm³ of water. When 0.02M solution of AgNO₃ was added to the mixture 13.45g of precipitate was formed. If SiCl₄ has a density of 1.48 g cm^-3, find the volume of SiCl₄ added to water.

Question 20

In each of the following reactions, balance the reaction and identify the oxidant and the reductant.

i)

ii)

iii)

iv)