Answer:
56°
Explanation:
First calculate 

The interplanar spacing can be calculated from:

The diffraction angle is determined from:

Solve for 

The diffraction angle is:

Answer:
is a reactant; it is present before the reaction occurs.
Explanation:
In a chemical reaction the chemical formulas written before the arrow are described as reactants as they react together to form products which are written after the arrow.

Thus
and HCl are reactants here whereas
,
and
are products.
Bubbles, release of gas, change in color, release of a smell, change in temperature, formation of a precipitate,