The image appears to be related to stoichiometry involving molarity and unit conversions. Based on the given equation, the student seems to be solving a problem related to molar concentrations. The missing part in the equation likely involves the unit conversion for volume or another relevant factor.

Let's break down the equation:

$\left( \frac{0.57 \, \text{mL}}{10^{-3} \, \text{L}} \right) \times \left( \frac{22.27 \, \text{g}}{\text{mol}} \right) = 26 \, \frac{\text{mol}}{\text{L}}$

Here’s the interpretation:

• The first term is converting milliliters (mL) to liters (L) by multiplying by $10^3$.
• The second term is converting grams (g) to moles (mol) using the molar mass $22.27 \, \frac{\text{g}}{\text{mol}}$.
• The final result is in units of mol/L (molarity).

It seems like the missing part is related to ensuring proper cancellation of units so that the final result will be expressed in mol/L. The missing unit in the equation is likely related to moles (mol) or grams (g).

Would you like me to go over the details of how to fill in the missing part of this equation? Feel free to ask for further clarification.