Misc: what is the right of succession or inheritance belonging to the eldest son?

Questions

Which great Asian river flows into the sea near Karachi?

Give another name for hydrocyanic acid (HCN), sometimes wrongly called cyanide?

Which charismatic but controversial European never won Wimbledon but was the first ATP number one ranked male tennis player in 1973?

Name the ship lost off Zuyder Zee in 1799 from which a famous item was salvaged in 1858?

At which battle did General James Scarlett lead the Charge of the heavy Brigade?