Question

if you had a mixture of ag⁺, na⁺ and ca²⁺, how many different solids could precipitate if cl⁻ ions were added?
no precipitate
1
2
3
question 56 (0.0862 points)
what is the charge on co in the compound co₂o₃
1+
2+
3+
4+

Explanation:

First Question (Precipitation)

Step1: Recall solubility rules

Chloride salts: $AgCl$ is insoluble, $NaCl$ is soluble, $CaCl_2$ is soluble.

Step2: Determine precipitates

Only $Ag^+$ forms a precipitate ($AgCl$) with $Cl^-$. So number of precipitates is 1.

Step1: Let charge of Co be $x$

Oxygen has a charge of $2^-$. In $Co_2O_3$, total positive charge = total negative charge.

Step2: Set up equation

$2x + 3\times(-2) = 0$ → $2x - 6 = 0$ → $2x = 6$ → $x = 3^+$.

Answer:

1 (the option "1")

Second Question (Charge on Co in $\boldsymbol{Co_2O_3}$)