11. In a titration to determine the concentration of hydronium ions in a test solution, the test solution was titrated with a 0.250 mol/L sodium hydroxide solution. Using 40.0 mL of test
solution, an average of 10.5 mL of sodium hydroxide solution was used to reach the
endpoint.

Calculate the molar concentration of the hydronium ion in the test solution. (1 point)

A) .0456 mol/L

B) 0.556 mol/L

C) .0656 mol/L

D). 0625 mol/L

Identify the correct relation showing that the radius r of the orbit of a moon of a given planet can be determined from the radius r of the planet, the acceleration of gravity at the surface of the planet, and the time τ required by the moon to complete one full revolution about the planet. determine the acceleration of gravity at the surface of the planet jupiter knowing that r = 71 492 km and that t= 3.551 days and r= 670.9 × 10^3 km for its moon europa.