Air China do not fly from Toronto Pearson to Beijing, so you must be on a different airline for at least that leg of the flight.
Presuming that airline is Air Canada, or at least some other carrier that uses terminal 3, then 1 hour 50 minutes is tight, but probably doable. The minimum connection time is 60 minutes, so you're above that means that the airline will (likely) re-route you if there is a problem - presuming both flights were booked on the same ticket.
You WILL need to go through some form of an immigration check. It's different to the immigration counter you'd go through to enter the country, and depending on the time of day the line at this area can be long - 30 minute or more delays are not uncommon.
Once you get through the immigration check there is a further security check, and then eventually you'll be let into the departure area to catch your connecting flight.
If you're using another airline that does not use terminal 3, then 110 minutes is NOT sufficient - even the minimum connection time is at least 2 hours depending on which terminals are involved.