Tin metal reacts with hydrogen fluoride to produce tin (ll )fluoride and hydrogen gas according to the balanced equation. Sn(s)+2 HF(g) - SnF2(s)+H2(g)

                      1.263 moles of HF

Explanation:

                     The balance chemical equation for given single replacement reaction is;

                                    Sn + 2 HF → SnF₂ + H₂

Step 1: Calculate Moles of Tin as;

As we know,

                    Moles  =  Mass / A.Mass     (1)

Where;

           Mass of Tin  =  75.0 g

           A.Mass of Tin  =  118.71 g/mol

Putting values in eq. 1;

                    Moles  =  75.0 g / 118.71 g/mol

                    Moles  =  0.6318 moles of Sn

Step 2: Find out moles of Hydrogen Fluoride as;

According to balance chemical equation,

                     1 mole of Sn reacted with  =  2 moles of HF

So,

              0.6318 moles of Sn will react with  =  X moles of HF

Solving for X,

                     X =  0.6318 mol × 2 mol / 1 mol

                     X  =  1.263 moles of HF

14 days is the half-life of phosphorus-32