Stoichiometry - Engineering

Q1:

The number of H+ in 1 c.c solution of pH 13 is

A 6.023 xl013

B 6.023 x 1010

C 6.023xl07

D 1013

ANS:C - 6.023xl07

To find the number of H+H+ ions in a solution given its pH, we first need to recall the definition of pH: pH=−log⁡[H+]pH=−log[H+] Where [H+][H+] is the concentration of H+H+ ions in moles per liter. Given that the pH of the solution is 13, we can rearrange the pH formula to solve for [H+][H+]: [H+]=10−pH[H+]=10−pH [H+]=10−13[H+]=10−13 [H+]=1×10−13 moles/L[H+]=1×10−13moles/L Now, we need to convert this concentration to the number of H+H+ ions in 1 cc (cubic centimeter) of the solution. Since 1 liter is equal to 1000 cc, we can use the following conversion: Number of H+ ions=[H+]×VolumeNumber of H+ ions=[H+]×Volume Number of H+ ions=(1×10−13 moles/L)×(1 L/1000 cc)Number of H+ ions=(1×10−13moles/L)×(1L/1000cc) Number of H+ ions=1×10−16 moles/ccNumber of H+ ions=1×10−16moles/cc To find the number of H+H+ ions in 1 cc of the solution, we use Avogadro's number, 6.023×1023 ions/mol6.023×1023ions/mol: Number of H+ ions=(1×10−16 moles/cc)×(6.023×1023 ions/mol)Number of H+ ions=(1×10−16moles/cc)×(6.023×1023ions/mol) Number of H+ ions=6.023×107Number of H+ ions=6.023×107 So, the number of H+H+ ions in 1 cc solution of pH 13 is 6.023×1076.023×107. Therefore, the correct option is 6.023×1076.023×107.