Qualitative analysis / by William Briggs and R.W. Stewart.

  • William Briggs
Date:
1913
Catalogue details

Licence: Public Domain Mark

Credit: Qualitative analysis / by William Briggs and R.W. Stewart. Source: Wellcome Collection.

    143/180 (page 127)
    Formate and Acetate. Heat the substance supposed to contain formate and acetate with dilute sulphuric acid in a boiling tube fitted with a cork and delivery tube (a small retort is better). The formic and acetic acids will be liberated, and should be collected in a second tube kept immersed in cold water. Divide the distillate into two portions, A and B. Portion A. Portion B. Add yellow mercuric oxide and shake till no more dis¬ solves. Warm gently ; re¬ duction will take place. F or- mic acid present. Add more mercuric oxide and heat till all the formic acid is de¬ stroyed. Filter. Neglect precipitate.—Fil¬ trate = mercuric acetate. • Evaporate to dryness and grind in a mortar with strong sulphuric acid. Smell of acetic acid. Neutralize with NaOH and evaporate to dryness. Divide into two portions, C and D. C. Heat with strong sul¬ phuric acid ; carbon monoxide evolved and burns at mouth of tube. Presence of formic acid confirmed. D. Heat with arsenious oxide in fume cupboard : indescribable odour of cac¬ odyl oxide. Presence of acetic acid confirmed.