@ green: IMO Aliya is impulsive and dumb, and it's likely that she doesn't know how to cook. Because of this, she chose to add detergent to the food rather than more salt or other spices.
Yes she's really stupid. Ever since Aliya was introduced, she has always shown as impulsive. She rushes into things and puts both herself and Armaan in trouble. But this time, her stupidity has harmed someone badly. Even small kids know that easiest way to spoil food is to add extra salt and spices. Aliya's problem is, she doesn't care about anyone other than herself. As long as she's not in trouble, she doesn't bother to think about the effect her actions can have on others. She wants to run away to Canada.. who cares if her father and family will be heartbroken. She wanted to use Aasmaa to get to Canada.. who cares if Aasmaa's life will be spoiled. This attitude is what makes her more problematic.