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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Quexkeh on August 12, 2021, 11:28:50 PM

Title: Reason for RSH > ROH in terms of acidity
Post by: Quexkeh on August 12, 2021, 11:28:50 PM

Comparing the acidity of RSH and ROH, RSH is more acidic. The reasons are that
1. S-H bond is weaker than O-H bond
2. Negative charge on RS- conjugate base can spread out to a larger surface area on S than on O, decreasing the charge density on S than O

What I said was
O > S in terms of electronegativity. Since in both compounds. Since the R group is the same(no change in electrodonating effecf), O would intensify the negative charge on RO- conjugate base more than S on RS-. Thus RSH is more acidic.

This was not accepted because "O or S electron withdrawing effect cannot be considered as it is the group in question"

Why can't I consider its electron withdrawing effect? I do not get it.

Title: Re: Reason for RSH > ROH in terms of acidity
Post by: rolnor on August 13, 2021, 12:51:01 AM

Why would O intensify the negative charge in RO-? What does electronegative mean?