Which of the following CANNOT become chametz on Pesach?
Halacha 1 states that kitniyot — including rice — do not become leavened. Even if rice flour rises, it is permitted because it merely decays, not leavens.
Question 2
If a person stops kneading and leaves dough at rest, after how long does it become chametz?
Halacha 13: dough left unattended for the time it takes to walk a mil becomes chametz.
Question 3
Who is permitted to make decorative thick matzot on Pesach?
Halacha 14 permits professional bakers to make designed thick loaves because they are skilled and quick. Private persons are forbidden lest they delay and cause leavening.
Question 4
A pot of food contains a wheat kernel that has NOT cracked open — what is the ruling?
Halacha 8: if kernels have not cracked open, the kernel must be removed and burned, but the rest of the dish remains permitted.
Question 5
Which earthenware vessel may NEVER be used for matzah on Pesach, even cold?
Halacha 20 singles out vessels used for yeast as having particularly powerful leavening absorbed into their walls — such earthenware may not be used at all, even for cold foods.