The drop-counter is misaligned with the buret, causing it to miss counting every one out of five drops of base added to the HCl. This error means the calculated molarity of the HCl solution will be its actual concentration.

Less than

Explanation:

According to the question, the drop counter is counting four out of five drops of base added to the HCl. So when the titration will reach to the end point the volume of Base recorded will be less than the actual volume of the base dropped in the solution.

We will use law of equivalence for the calculation of concentration of HCl,

Where, and are molarity and volume of HCl and and are molarity of volume of the base added.

Thus concentration of HCl will be calculated as,

As the recorded is less than the actual amount present in the solution, the calculated value of concentration of HCl will also be less than the actual.