To solve this problem, we need to understand the nature of phosphinic and phosphonic acids.$\newline$Phosphinic acid and phosphonic acid are both phosphorus-containing acids, but they differ in their structure and acidity.$\newline$Let's analyze each one:$\newline$• Phosphinic acid (also known as hypophosphorous acid) has the formula $H_3PO_2. \newline$• In phosphinic acid, only one hydrogen atom is ionizable, making it a monoprotic acid.$\newline$• The structure of phosphinic acid is $H_2P(O)OH,$ where only the hydrogen attached to the oxygen is acidic.$\newline$• Phosphonic acid has the formula $H_3PO_3. \newline$• In phosphonic acid, two hydrogen atoms are ionizable, making it a diprotic acid.$\newline$• The structure of phosphonic acid is $HP(O)(OH)_2,$ where both hydrogens attached to the oxygens are acidic.$\newline$Based on this analysis:$\newline$• Phosphinic acid is a monoprotic acid.$\newline$• Phosphonic acid is a diprotic acid.$\newline$Therefore, the correct statement is:$\newline$Option 1: Phosphinic acid is a monoprotic acid while phosphonic acid is a diprotic acid.