Group 7 PMT (q. 1-16)

• add HCl + BaCl2

• white ppt

• no. of electrons increases down the group- from chlorine to iodine

• the strength of the London forces increases and more energy is needed to overcome the London forces

lower:

• HClO will be lower

• ineffective as a disinfectant

higher:

• HCl will be higher

• increases toxicity/ acidity

• excess dilute ammonia and the ppt is insoluble

• excess conc. ammonia and it is soluble

Give a reason why dilute hydrochloric acid is needed to test for sulfate ions?

To remove any carbonate/ sulfite

Disproportionation is an equilibrium system

The covalent bond in HCl changes to an ionic bond in aqueous solution

NH4Br

Write the ionic equation for the reaction between ammonium cation and sodium hydroxide producing the gas

Write the ionic equation for the reaction between aqueous solutions of sodium iodide and silver nitrate. Include state symbols

Ionic half-equation for the reduction of chlorine molecules to chloride ions.

Ionic half-equation for the oxidation of chlorine molecules to chlorate(I) ions in the presence of cold, aqueous hydroxide ions