Therefore, if Zhang Qiang's conjecture is correct, then the experimental phenomena in devices B and C are: there is no obvious change in limewater, and the color of chicken blood is carmine;
If Wang Mei's guess is correct, the experimental phenomena in devices B and C are: lime water becomes turbid and chicken blood is carmine.
So the answer is: there are bubbles in B, there is no phenomenon in the clarified limewater, and the chicken blood in C is carmine;
The clarified limewater in B becomes turbid, and the chicken blood in C is carmine;
(4) Carbon monoxide is a toxic gas. When using carbon monoxide, there must be a tail gas treatment device. A pointed glass tube and a burning alcohol lamp can be connected at the outlet of device C (the tail gas at the outlet of device C can also be collected by balloons or plastic bags).
So, the answer is: burn or collect with balloons;
(5) Charcoal can reduce CuO, so it is reducible and can be used to smelt metals.
So the answer is: smelting metal.