>>12556932Looks like the basic ammonia may attack the H+ in the (NH4)HCO3, which forms another ammonium ion (NH4+) which forms the final product with the NH4CO3- that lost the proton. So in other words, it really doesn't matter too much the strength of your ammonia solution, but it is somewhat soluble in water, so to separate it from the solution once the reaction is completed it will be more convenient to use a solution with less water so the water can be evaporated much faster (this will especially take longer since trying to speed up the evaporation via heating can decompose your product). You just need enough water to completely dissolve your ammonium bicarbonate, and then add a strong(ish, doesn't really matter too much) ammonia solution, and then evaporate the water to isolate the product (without heating). Should work fine.
