Hydrogen cyanide, HCN , behaves in a water solution very...

Hydrogen cyanide, HCN , behaves in a water solution very much like the binary covalent compounds of hydrogen, but it liberates the cyanide ion, $\mathrm{CN}^{-}$, a deadly poison, which can disrupt the body's ability to utilize oxygen. Name the acidic water solution by following the rules for binary covalent compounds of hydrogen.

Key Concepts

Binary Covalent Compound Nomenclature

This concept involves the systematic naming of compounds made from two nonmetals, one of which is hydrogen. In binary covalent compounds, prefixes are typically used to indicate the number of atoms, and when the compound behaves as an acid in solution, the nonmetal is often given a modified name (usually with an -ic ending) following a 'hydro-' prefix. This convention helps in identifying the molecular composition and properties of the compound.

Acidic Solution Behavior and Nomenclature

When a binary covalent compound containing hydrogen is dissolved in water, it forms an acidic solution by donating protons (H+ ions). The naming of such acidic solutions follows specific rules: the compound is typically named with a 'hydro-' prefix attached to the element’s root name and an '-ic acid' suffix. This nomenclature indicates that the compound is an acid and gives insight into its chemical behavior in aqueous solution.

Transcript

00:01 Okay, in this question we are looking at a cyanide ion and we're adding an h plus ion to it.

00:08 And we're trying to predict where the h plus is going to go on the structure.

00:12 So the first step to solving this is to draw the right low structure.

00:16 We have four electrons from the carbon, five from the nitrogen, and we're going to add an electron because of this negative charge.

00:25 That means we have 10 valence electrons to share around the cyanide ion.

00:30 Ion.

00:31 And let's draw our structure.

00:33 So we have a c for carbon, triple bonded to nitrogen, and we're going to put a loan pair on each the nitrogen and the carbon.

00:46 If we add these up, we have two electrons here.

00:49 We have six over here, and we have two over here.

00:51 That equals 10.

00:53 So we're all set in terms of valence electrons.

00:58 And now we have to figure out it's the hydrogen.

01:01 To go over here.

01:03 Where is it going to go over here? so the way we solve that is by looking at formal charges.

01:12 Remember, with the electron neutrality theory, stable molecules prefer to have their, most of their atoms have a near zero charge.

01:24 So let's look at what happens if we bond the hydrogen to the carbon.

01:35 The formal charge of the hydrogen is equal to one valence electron minus zero non -bonding, minus two bonding over two...

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