Chemistry, 23.07.2019 21:00 gungamer720

The acid-dissociation constant of hydrocyanic acid (hcn) at 25.0 °c is 4.9 ⋅ 10−10. what is the ph of an aqueous solution of 0.080 m sodium cyanide (nacn)?

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Answer from: swello1937

According to the reaction equation:

and by using ICE table:

CN- + H2O ↔ HCN + OH-

initial 0.08 0 0

change -X +X +X

Equ (0.08-X) X X

so from the equilibrium equation, we can get Ka expression

when Ka = [HCN] [OH-]/[CN-]

when Ka = Kw/Kb

= (1 x 10^-14) / (4.9 x 10^-10)

= 2 x 10^-5

So, by substitution:

2 x 10^-5 = X^2 / (0.08 - X)

X= 0.0013

∴ [OH] = X = 0.0013

∴ POH = -㏒[OH]

= -㏒0.0013

= 2.886

∴ PH = 14 - POH

= 14 - 2.886 = 11.11

Answer from: giuliabril

The pH of the solution is calculated to be 5.22.

First we must set up the table for the reaction:

Let the cyanide ion be represented by X

HX(aq) ⇄ H^+(aq) + X^-(aq)

I 0.08 0 0

C -x +x +x

E 0.08 - x x x

We now obtain the Ka of the solution as follows;

Ka = [H^+] [ X^-]/[HX]

4.9 × 10^−10 = x^2/ 0.08 - x

4.9 × 10^−10(0.08 - x) = x^2

3.92 × 10^11 - 4.9 × 10^−10x = x^2

x^2 + 4.9 × 10^-10x - 3.92 × 10^-11 = 0

x = 0.000006 M

Now, the pH of the solution is obtained from;

pH = - log(0.000006 M)

pH = 5.22

Hence, the pH of the solution is calculated to be 5.22.

Learn more about pH: link

Answer from: Quest

Since there is the same amount of agn03 in both silver chloride and silver nitrate they produce the same amount of moles. therefore silver chloride produces the same amount of silver nitrate, so your answer is 15.0 moles of silver nitrate. i hope this !

Answer from: Quest

he uptake of drugs from the intestine is often strongly influenced by diffusion. for example, consider a water-insoluble steroid for treating inflammation that is solubilized in aggregates of detergent molecules, called micelles. these micelles, aggregates of 80 soap molecules, have a molecular weight of 24,000, a diameter of 2.6 nm, and a charge of -27. the positively charge ions (counterions) in this system are na".

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