Misc: Duets - Brandy and ______________ had a No.1 with 'The Boy Is Mine' in 1998?

Questions

In area, which is the largest country in Africa?

Which ex-Neighbours star released the No.2 hit single "Tom" in October 1997?

Which liqueur gives the cocktail "Tequila Sunrise" its red glow?

Which book caused a minor controversy in 1997 when a survey of Waterstone's customers voted it the best book of the twentieth century?

Who deposed Helmut Kohl as Chancellor of the Federal German Republic in 1998?