The certificate of acknowledgment heretofore taken of a married woman to a deed or other writing conveying, or agreeing to sell and convey, real estate which was her sole and separate property, purporting to show that at the time of its execution and acknowledgment such married woman was living separate and apart from her husband, shall, in all cases where the validity of any such deed or other writing comes in question, be prima facie evidence of the facts therein stated.