Answer:
False.
Step-by-step explanation:
Why? Because Chemical Weapons are at the end of the day, gas. Gas could be effected by the wind, easily being redirected at friendly combatants. It also isn't a guaranteed killer, as gas masks prevented fatalities. Don't get me wrong, if you were caught without a gas mask you were as good as dead, but you had safety from the gas if you wore a gas mask. However, you could get sick from the residue on your uniform, perhaps even die from it. On a psychological perspective, it was terrifying. Imagine this; you're in a trench and you hear your Sergeant yelling "Gas, Gas, Gas!". You are now frantically trying to put on your mask so you won't die, and it's truly a race against time. The amount of stress you'd be under is substantial. From a strategic perspective, gas did weaken the enemy line, but over time people got used to it and eventually just became a way of terrible life, even if it was terrifying.