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Molar mass: 59.072 g·mol −1 ... [2] (pK b of 0.4) meaning that guanidine is a very strong base in water; in neutral water, it exists almost exclusively as ...
C(NH 2) + 3 + OH − ⇌ HNC(NH 2) 2 + H 2 O. The equilibrium is not complete because the acidity difference between guanidinium and water is not large. The approximate pK a values: 13.6 vs 15.7. Complete deprotonation should be done with extremely strong bases, such as lithium diisopropylamide. C(NH 2) + 3 Cl − + Li + N(C 3 H 7) − 2 → ...
Guanidinium thiocyanate can be used to deactivate a virus, such as the influenza virus that caused the 1918 "Spanish flu", so that it can be studied safely.. Guanidinium thiocyanate is also used to lyse cells and virus particles in RNA and DNA extractions, where its function, in addition to its lysing action, is to prevent activity of RNase enzymes and DNase enzymes by denaturing them.
For example, reaction with sodium sulfide produces the brown/black tin(II) sulfide: SnCl 2 (aq) + Na 2 S (aq) → SnS (s) + 2 NaCl (aq) If alkali is added to a solution of SnCl 2, a white precipitate of hydrated tin(II) oxide forms initially; this then dissolves in excess base to form a stannite salt such as sodium stannite:
SnO 2 + 2 KSCN → SnS + K 2 S + 2CO + N 2. SnS also forms when aqueous solutions of tin(II) salts are treated with hydrogen sulfide. [5] This conversion is a step in qualitative inorganic analysis. At cryogenic temperatures, stannous chloride dissolves in liquid hydrogen sulfide. It then decomposes to the sulfide, but only slowly. [6]
This reaction is rapid and stoichiometric, with the addition of one mole of thiol releasing one mole of TNB. The TNB 2− is quantified in a spectrophotometer by measuring the absorbance of visible light at 412 nm, using an extinction coefficient of 14,150 M −1 cm −1 for dilute buffer solutions, [4] [5] and a coefficient of 13,700 M −1 cm −1 for high salt concentrations, such as 6 M ...
Tin sulfide can refer to either of these chemical compounds: Tin(II) sulfide, SnS; ... This page was last edited on 2 December 2024, at 03:36 (UTC).
Tetramethylguanidine is an organic compound with the formula HNC(N(CH 3) 2) 2. This colourless liquid is a strong base, as judged by the high pK a of its' conjugate acid. [2] It was originally prepared from tetramethylthiourea via S-methylation and amination, but alternative methods start from cyanogen iodide. [3]