6. Which of the following trends going down group 7 from chlorine to iodine is not true?
their anions of formula X− form precipitates with aqueous silver ions
the first ionisation energy becomes less endothermic
the strength of the halogen as an oxidising agent increases
their compounds with hydrogen are acids
7. What is the colour of methyl orange at the end point of a titration in which an alkali is added to an acid?
yellow
orange
pale pink
red
8. Radium occurs below barium in group 2. On the basis of the trends in the chemistry of group 2, which of the following statements is true?
Radium carbonate is very soluble in water.
Radium hydroxide is more soluble in water than calcium hydroxide
Radium carbonate is more easily decomposed by heating than magnesium carbonate.
Radium sulfate is more soluble in water than magnesium sulfate.
9. In a titration, the mean titre of a 0.123 mol dm−3 solution of sodium hydroxide was 24.45 cm3. The amount (in moles) of sodium hydroxide in the mean titre was
