hclo4, hcl, h3po4, or hcn?
im leaning towards hcl
2007-03-01 09:26:41 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
H3PO4 and HCN are weak acids
HClO4 and HCl are extremely strong acids and it is rather difficult to say. According to the values given by wikipedia I'd expect HCl to be slightly stronger (pKa (HClO4)= -7 and pKa(HCl)= -8). However according to other sources HClO4 is stronger: pKa (HClO4)= -10 and pKa(HCl)=-7. Also in this source HClO4 is said to be as strong as HI (which is definetely stronger than HCl), so I believe that HClO4 is stronger and in wikipedia there is a deviation because such pKa values are not extremely accurate and can vary depending on the source.
I am refering to the HCl pKa value at http://chemweb.unp.ac.za/chemistry/Physical_Data/pKa_values.htm
and the HClO4 pKa value mentioned on the pdf that they refer to on that page
2007-03-01 09:44:39 · answer #1 · answered by bellerophon 6 · 0⤊ 0⤋
You are correct. Check the dissociation constant for each acid.
pKa for HCl = -8.0
HClO4 = -7.0
H3PO4 = 2.12 (first proton)
HCN = 9.2
The pKa shows the degree of dissociation of the acid, smaller is stronger.
2007-03-01 09:46:56 · answer #2 · answered by Anonymous · 0⤊ 0⤋
a 38% concentration of HCl has a PH of -1.1, making it the most acidic substance.
2007-03-01 09:34:13 · answer #3 · answered by vanchuck 2 · 1⤊ 1⤋