# chemistry

posted by .

Calculate the pH of an aqueous solution containing 1.6 x 10-2 M HCl, 2.0 x 10-2 M H2SO4, and 1.8 x 10-2 M HCN.

• chemistry -

This is not nearly as easy as it looks. The simple way to do it is to add H^+ from 0.016M HCl, 0.02M H2SO4(first H^+ ONLY) and ignore the H^+ from k2 for H2SO4 and H^+ from HCN (weak acid).
You can go through the math but the second H from H2SO4 contributes only 0.0046 but compared to 0.036 from above probably should be added in. If you want to do that use
k2 = (H^+)(SO4^-)/(HSO4^-). For (H^+) substitute x+0.036 and for (SO4^2-) substitute x and for (HSO4^-) substitute 0.02-x. I get 0.00456M for k2 contribution from H2SO4. For the HCN; that is
HCN ==> H^+ + CN^-
Ka = (H^+)(CN^-)/(HCN) = 2.1E-9
(x+0.04056)/(0.018) = about 3E-6 which can be ignored.
Then pH = -log(H^+).
Post your work if you get stuck.

## Similar Questions

1. ### Chemistry

Calculate the equilibrium concentration of all ionic aqueous species in a solution containing 1.30 M HCl and 4.0 M C6H5OH (phenol, Ka=1.6 x 10^-10). What is the pH of the solution?
2. ### AP Chemistry

An aqueous sulfuric acid solution containing 571.6 g of H2SO4 per liter of solution at 20°C has a density of 1.3294 g/mL. Calculate (a) the molarity, (b) the molality, (c) the percent by mass, and (d) the mole fraction of H2SO4 for …
3. ### chemistry

What is the percent by mass of 3.55 g NaCl dissolved in 88 g H2O?
4. ### Chemistry

When potassium cyanide (KCN) reacts with acids, a deadly poisonous gas, hydrogen cyaninde (HCN) is given off. Here is the equation: KCN(aq) + HCl(aq) ----> KCl(aq)+ HCN(g) If a sample of 0.140 g of KCN is treated with an excess …
5. ### Chemistry

Calculate the pH of an aqueous solution containing 3.8 10-2 M HCl, 1.0 10-2 M H2SO4, and 3.3 10-2 M HCN.
6. ### Chemistry

Calculate the pH of an aqueous solution containing 3.8 10-2 M HCl, 1.0 10-2 M H2SO4, and 3.3 10-2 M HCN.
7. ### Science

Calculate the pH of an aqueous solution containing 1.3 * 10^-2 M HCl, 3.0 * 10^-2 M H2SO4, and 2.0 * 10^-2 M HCN.
8. ### Chemistry

H2SO4 solution containing 200.1 g of H2SO4 in 0.3500 L OF solution has a density of 1.3294 g/ml.calculate (A) Mass%H2SO4(m/m) (B)mass%H2O(m/m) (C)Molarity (D)Molality
9. ### Chemistry

My chemistry is bad. I know these are very easy but I cannot solve them . 1. a) Prepare 200 ml of 2 M HCl solution from stock bottle containing 37% w/w HCl and d = 1.2 (g/ml). MWHCl = 36.5 g b) Calculate M of 37% w/w HCl solution?
10. ### Chemistry

How much sulphuric acid containing 90% H2SO4 by wt. is needed for the production of 1000 kg of HCl containing 42% HCl by weight in this reaction. 2NaCl + H2SO4 -----> Na2SO4 + 2HCl

More Similar Questions