Formaldehyde % solution

[hCiLdOdUeDn]

Swim distilled a solution of excess paraformaldehyde with water at regular atmospheric pressure to make a formaldehyde solution. The p-formaldehyde dissolved in the water but some didnt dissolve because swim had excess paraformaldehyde.  What % formaldehyde solution is left in the recieving flask? Swim is guessing its a 37% solution, as most formaldehyde solutions are. Is this correct. Thanks.

[hCiLdOdUeDn]

need help^^

[raffike]

You may also have lots of trioxymethylene in that flask.

          Formaldehyde solution, Formalin, Formol, Morbicid, Veracur (Typharm).  A soln of about 37% by wt of formaldehyde gas in water, usually with 10-15%
  methanol added to prevent polymerization.  This soln is the full strength and also known as Formalin 100% or Formalin 40 which signifies that it contains 40 grams of
  formaldehyde within 100 ml of the soln.  Colorless liq; pungent odor.  On standing, esp in the cold, may become cloudy and on exposure to very low temp a ppt of
  trioxymethylene is formed.  When evaporated, some formaldehyde escapes, but most of it is changed to trioxymethylene.  It is a powerful reducing agent especially in
  presence of alkali.  In the air it slowly oxidizes to formic acid.  d2525 1.081-1.085.  One gallon weighs 9.1 lbs.  bp760 96 deg.  nD20 1.3746.  Flash pt 60 deg (140 degF).  pH 2.8-4.0. 
  Misc with water, alcohol, acetone.  Keep well closed in a moderately warm place.  LD50 orally in rats:  0.80 g/kg (Smyth).