Under what conditions can hydrogen behave as a metal?

Tritium is an isotope of

Which of the following is an electron-precise type of hydride?

Which of the following is expected to be high for a proton $(H^+)$?

Which of the following upon hydrolysis can produce a hydrocarbon that has the same degree of unsaturation as the number of carbon atoms present in the produced hydrocarbon?

Which of the following statements is incorrect?