Misc: sound travels fastest in which form of medium?

Questions

In 1972 US began its heaviest bombing of North---------- . ?

In 1973 Soyuz 13 launched into ---------- orbit for 8 days. ?

In 1980 Soviet Premier Alexei ---------- suffered a fatal heart attack at 76. ?

In 1985 UN ---------- Council unanimously condemns 'acts of hostage-taking'. ?

In 1683 Philip V, first Bourbon king of ---------- (1700-46) ?