yes you can stall in gear 2. in fact you stall it more likely in
gear 2 than in gear 1, ceteris paribus.
from my own theory, engine stalls because the throttle applied to
it is not enough to overcome the inertia of the vehicle, hence it
stalls. when a car is at low speed, it does not carry enough
momentum, so more force is required to accelerate it. if the
throttle is not enough, the engine experiences more resistance and
dies. as you should have learnt in theory, the lower gear, the
greater the force, and vice versa.
correct me if i'm wrong. 
