[Win,odd Dhamnekar]

In all the following exercises M represents metal and X represents anion.


a) The salt, MX₂ has a K_sp of 2.00e-6. If equal volumes of 0.0059M M(NO₃)₂ and 0.01M NaX are mixed, will solid form?

b)The salt, MX₃ has a K_sp of 2.07e-10. If equal volumes of 0.0029M M(NO₃)₃ and 0.02M NaX are mixed, will solid form?

c)The salt, MX has a K_sp of 2.13e-6. If equal volumes of 0.0062M M(NO₃)₂ and 0.03M Na₂X are mixed, will solid form?

My worked out answers:

a)Q_ion=0.00295*0.01²=2.95e-7 which is less than the given K_sp 2.00e-6, hence solid won't form.

b)Q_ion=0.00145*(0.03)³=3.915e-8 which is greater than the given K_sp 2.07e-10, hence, solid will form.

c)Q_ion=0.0031*0.015= 465e-5 which is greater than the given K_sp 2.13e-6, hence solid will form.

What is your opinion about these answers? Are these answer correct? In my opinion, all  these three answers are correct.

[mjc123]

Where do you get the value 0.03 in b? Or 0.01 in a?

[Win,odd Dhamnekar]

In b) , Initial concentration of salt MX₃ is 0.02M.After mixing equal volumes of metal(M) and anion(X), it will be 0.01. Then it will be multiplied by X's subscript in MX₃=0.03.

Similar is the case for (a).

[mjc123]

You don't have MX₃, you have M(NO₃)₃ and NaX. After mixing, you have 0.00145 M M³⁺ and 0.01 M X^-.

You mustn't assume there are stiochiometric  amounts of M and X!