Step-by-step explanation:
It is necessary that the glassware which we use during titration needs to be clean and dry before use because otherwise the remaining reagents will get mixed up with the solutions.
As a result, this will lead to a change in analysis results.
Hence, an error will occur in the resulting values.
Also, when not cleaned properly the any other substance remaining in the glassware might react with the solution leading to a change in the solution.
In that case also, error will occur.