Suppose you used 0.5 M NaOH to titrate your vinegar sample instead of 0.1 M. What effect does the concentration of base added have on the reliability of the results of your titration?

the reliability will be worse

Explanation:

Suppose we used 0.5 M NaOH to titrate our vinegar sample instead of 0.1 M.

Now by using 0.5M instead of 0.1M we are increasing the concentration of NaOH,

We know that  the moles used = Volume x concnetration.

so for the same no of moles, if the concentration increases, the volume decreases.

Hence it will consume less NaOH.

now Since the volume decreases, the titration volume of less number will increase the % error.

Therefore the reliability will be worse.      

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).