右图中的实验装置可用于制取乙炔.
请填空:
(1)图中,A管的作用是________________________________
____________________________________________________,
制取乙炔的化学方程式是_______________________________
________________________________________________________________________.
(2)乙炔通入KMnO4酸性溶液中观察到的现象是______________________________,乙炔发生了________反应.
(3)乙炔通入溴的CCl4溶液中观察到的现象是______________________________,乙炔发生了________反应.
(4)为了安全,点燃乙炔前应______________________,乙炔燃烧时的实验现象是________________________________________________________________________.