From the conservation of mass, matter is not created nor
destroyed. So ponder it this way, for example I put one piece of toast in a
toaster, but when it is done I had two pieces, that makes no sense right? Same
thing with a chemical reaction but in molecular terms, all things must stay constant.
If you put a convinced amount you have to get that quantity back, not less or
not more in broad terms.
They cant hold the pressure
The *independent* variable is the one that you always can control. However, the dependent variables are not since they **depend** on another.
Answer : The answer is,
Explanation :
Scientific notation : It is defined as the way or representation of expressing the number that are too big or too small that is written in the decimal form. That means always written in the power of 10 form.
For example : 8000 is written as,
in this notation, the significant figure is, 1 but
in this notation, the significant figures are, 2
The given problem are :

According to the divide and multiplication rules of scientific figures, the final answer is only as precise as the value with the least number of significant figures.
Hence, the answer is,
Sodium chloride and prussic acid are formed
NaCN+HCl→NaCl+HCN