Question

For crease resist finishing of cotton, 70 gpl aqueous solution of DMDHEU (molecular weight - 178) is applied by padding. If the DMDHEU is available as 50% (w/v) aqueous solution, then the required amount of DMDHEU solution (ml) for preparation of 1000 ml padding liquor is:

Hint:

For preparing a specific concentration from a stock solution, use the formula: \( C_1 V_1 = C_2 V_2 \) where \(C_1\) and \(V_1\) are the concentration and volume of the stock solution, and \(C_2\) and \(V_2\) are the desired concentration and volume.

Answer 1

The required amount of DMDHEU solution can be calculated using the formula: \[ {Required solution (ml)} = \frac{{Desired concentration} \times {Total volume of liquor}}{{Concentration of stock solution}} \] Step 1: Calculate the required amount of DMDHEU.
The desired concentration is 70 gpl (grams per liter), which means 70 grams of DMDHEU is required for 1 liter of the liquor. \[ {Amount of DMDHEU required} = 70 \, {g} \] Step 2: Calculate the volume of 50% (w/v) DMDHEU solution needed.
The stock solution is 50% (w/v), meaning there are 50 grams of DMDHEU in 100 mL of solution. The volume of 50% solution required is: \[ {Required volume (ml)} = \frac{70 \, {g} \times 100}{50 \, {g}} = 140 \, {ml} \] 
Correct Answer: 140