I cannot figure out the equation and answer to the following. Can someone help please.
A 25.0 mL solution of HCl has been spilled. It took 21.8 mL of saturated 2.5 M NaOH to neutralise the acid. What was the molar concentration of the acid?
HCl + NaOH ==> NaCl + H2O
mols NaOH used = M x L = ?
mols HCl neutralized = mols NaOH
M HCl = mols HCl/L HCl
I think this was asked before:
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Is Sarah the same as Campbell?
To find the molar concentration of the acid (HCl), you can use the concept of stoichiometry and the equation of the reaction between HCl and NaOH.
The balanced chemical equation for the reaction is:
HCl(aq) + NaOH(aq) -> NaCl(aq) + H2O(l)
From the equation, we can see that 1 mole of HCl reacts with 1 mole of NaOH. This means the mole ratio between HCl and NaOH is 1:1. Therefore, the number of moles of HCl that reacted can be determined by:
moles of HCl = moles of NaOH
To find the moles of NaOH, we can use the molarity and volume of NaOH used during the neutralization:
moles of NaOH = Molarity of NaOH × volume of NaOH (in liters)
Since the volume of NaOH used is given in milliliters, we need to convert it to liters by dividing it by 1000.
volume of NaOH (in liters) = 21.8 mL / 1000 = 0.0218 L
Substituting the given values into the equation:
moles of NaOH = 2.5 M × 0.0218 L = 0.0545 moles
Since the mole ratio with HCl is 1:1, the moles of HCl are also 0.0545 moles.
Now, we can determine the molar concentration of HCl by dividing the moles of HCl by the volume of the HCl solution:
Molarity of HCl = moles of HCl / volume of HCl solution (in liters)
The volume of the HCl solution is given as 25.0 mL, so we need to convert it to liters by dividing it by 1000.
volume of HCl solution (in liters) = 25.0 mL / 1000 = 0.0250 L
Substituting the values into the equation:
Molarity of HCl = 0.0545 moles / 0.0250 L = 2.18 M
Therefore, the molar concentration of the acid (HCl) is 2.18 M.