Misc: Substance that neutralizes alkalis and turns litmus paper red?

Questions

"Poppy Field" and "Water Lilies" were painted by which artist?

What ingredient is contained in beer but not ale?

The novel "Weir of Hermiston" was an unfinished novel by which writer?

Which capital city was originally scheduled to hold the 1940 Summer Olympics, and had to wait for twenty-four years?

Which trophy is inscribed "The Gentlemen's Single-Handed Championships of the World"?