Final answer:
The statement is true; phosphoric acid, which is used in the automotive industry, contains approximately 31.63% phosphorus by mass.
Step-by-step explanation:
The statement that an acid commonly used in the automotive industry is shown to be 31.6% phosphorus can be assessed as True or False based on the acid in question. If the acid in question is phosphoric acid (H3PO4), which is indeed used in the automotive industry for metal cleaning and rust removal among other applications, then we need to calculate the percentage composition of phosphorus to verify the statement.
The molar mass of phosphoric acid is approximately 98 g/mol (1 P x 31 + 3 H x 1 + 4 O x 16). The molar mass of phosphorus (P) is about 31 g/mol. To find the percent composition of phosphorus in phosphoric acid, we divide the molar mass of phosphorus by the molar mass of phosphoric acid and multiply by 100%:
Percentage of P in H3PO4 = (31 g/mol / 98 g/mol) x 100% = 31.63%
Therefore, the statement is True; phosphoric acid, which contains approximately 31.63% phosphorus, is commonly used in the automotive industry.