Answer: Because hydrogen is a gas.
Explanation: If children were running around with balloons filled with hydrogen gas, then they would catch fire. So the answer to your question is, its simply dangerous.
Answer:

Explanation:
1. Calculate the rate constant
The integrated rate law for first order decay is

where
A₀ and A_t are the amounts at t = 0 and t
k is the rate constant

2. Calculate the half-life

Answer:
The nitrile group
Explanation:
The nitrile group contains the C≡N bond. It should be recalled that triple bond is highly electronegative and withdraws electrons from the C-H bond more effectively than the halogen atom.
The higher effectiveness of the C≡N bond at electron withdrawal greatly reduces the electron density of the C-H bond thereby making the hydrogen atom of the bond highly labile