113:2 On erev Pesach, it is prohibited to eat chometz after one-third of the day, counting from dawn until the stars come out. (Some say from sunrise to sunset, which turns out to be lenient in this matter; it is advisable to follow the stringent opinion – Mishnah Brurah 443:8.) One is permitted to use chometz for one hour longer, during which time one may sell it to a non-Jew; after this, it is also forbidden to use it. One must burn the chometz and nullify it during the time period when it is still permitted for use. (In a case of emergency, one may sell it until an hour before noon – MB 443:9.)
113:3 From midday on, acts of creative labor (melacha) are prohibited; one may only do those things that are permitted on chol hamoed. (A worker who has nothing to eat may work to have money to buy food – MB 468:6.) The accepted practice is to permit work done through a non-Jew (even in the Jew’s home – MB 468:5). Some communities have the practice to prohibit labor the entire day (starting at sunrise; the whole night is permitted – MB 468:11).