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What is the corrosion rate of a steel rod with a surface area of 10 cm2 in a solution of 0.1 M HCl at 25◦C if the current passing through the rod is 0.5 A for 5 hours? The atomic weight of steel is 56 g/mol and its density is 7.86 g/cm3.

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To calculate the corrosion rate of the steel rod, we can use Faraday's law of electrolysis, which states that the mass of a substance deposited or dissolved at an electrode during electrolysis is directly proportional to the quantity of electricity passed through the electrolyte.First, we need to determine the total charge passed through the rod. The total charge  Q  can be calculated using the formula:Q = I  twhere I is the current  0.5 A  and t is the time  5 hours  3600 seconds/hour = 18000 seconds .Q = 0.5 A  18000 s = 9000 CoulombsNow, we can use Faraday's law to calculate the mass of steel corroded. The formula is:m =  Q  M  /  n  F where m is the mass of steel corroded, Q is the total charge, M is the atomic weight of steel  56 g/mol , n is the number of electrons involved in the reaction  for steel, it's 2 because it loses 2 electrons to form Fe , and F is Faraday's constant  96485 C/mol .m =  9000 C  56 g/mol  /  2  96485 C/mol  = 2.61 gNow that we have the mass of steel corroded, we can calculate the volume of steel corroded using the density formula:Volume = mass / densityVolume = 2.61 g / 7.86 g/cm = 0.332 cmTo find the corrosion rate, we can divide the volume corroded by the surface area and time:Corrosion rate = Volume /  Surface area  Time Corrosion rate = 0.332 cm /  10 cm  5 hours  = 0.00664 cm/hourThe corrosion rate of the steel rod is approximately 0.00664 cm/hour.

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