Answer variants:
\(100\) \(g\) \(A\) : after one hour : \(50\) \(g\) \(A\) is left
\(100\) \(g\) \(A\) : after one hour : \(30\) \(g\) of \(A\) is left
 
1. Fastest reaction:
 
2. Slowest reaction: