The answer to this question would be: <span>NaOH solution 
Limiting reagent is the reagent that totally consumed in the reaction. To answer this question you need to know the equation for the chemical reaction. The equation would be:
</span><span>HCl + NAOH = H2O + NACl
</span>
All of the coefficient in the reaction is 1, which mean 1 HCl will react to 1 NaOH. In this question, the concentration of HCl and NaOH is same so the amount of the molecule can be reflected by the volume. NaOH has lower volume compared to HCl so it is clear that NaOH will be totally consumed in this reaction. 
        
                    
             
        
        
        
Answer:
            5.645 × 10⁻²³ g
Solution:
Step 1) Calculate Molar Mass of SH₂;
Atomic Mass of Sulfur    =  32 g/mol
Atomic Mass of H₂         =  2 g/mol
                                      --------------------
Molecular Mass of SH₂  =  34 g/mol
Step 2: Calculate mass of one molecule of SH₂ as;
As,
                     Moles  =  # of Molecules / 6.022 × 10²³
Also, Moles  =  Mass / M.Mass So,
                     Mass/M.mass  =  # of Molecules / 6.022 × 10²³
Solving for Mass,
                     Mass  = # of Molecules × M.mass / 6.022 × 10²³
Putting values,
                     Mass  =  (1 Molecule × 34 g.mol⁻¹) ÷ 6.022 × 10²³
                     Mass  =  5.645 × 10⁻²³ g