乙炔(C₂H₂)是一种难溶于水、密度比空气略小、易燃烧的气体，完全燃烧生成两种氧化物。实验室用碳化钙（俗称电石，化学式为CaC₂）与水常温下反应制取乙炔。

根据上图回答下列问题。

(1)制备乙炔的反应装置应选用的仪器是____；收集乙炔的方法是__________。

(2)点燃乙炔之前应先__________；写出乙炔完全燃烧的化学方程式________________。

Which condition represents the appropriate time for setting off distress flares and rockets? （）

A.At one hour intervals

B.At half hour intervals

C.Only when there is a chance of their being seen by rescue vessels

D.Immediately upon abandoning the vessel