Question

Can you please solve the below questions? From chapter (half life, she’ll life, f’zero, first, second order reaction) please explain in details with the calculations. Thanks!

3. A 5 gm/100 ml solution of drug X is stored in a closed test tube at 25°C. If the rate of degradation of the drug is 0.05 day-1, calculate the time required for the initial concentration to drop to (a) 50% (half -life) and (b) 90% ( shelf-life) of its initial value. 4. A 5 gm/100 ml solution of drug X is stored in a closed test tube at 25°C. If the rate of degradation of the drug is 0.05 day-1, calculate the time for the drug concentration to degrade to 2.5 mg/ml.

Answer 1

5gm / 100ml.. tot, k: 0.05 day", Co: from the unit of rate of degradation the Hoction is of first order for a first order reaction Inc = enco-kt o where is concentration at time to or initial core". c is lone" after time time t.. k is the digndation constant or rate constant @ 501 or half life betta ty, and c lo So Equation @ becomes. Into = enco-kty or en torento = -Kt, - 5000 mg Too ml = 50 mg & C = 2.5 mg en 2.5 mg - en 50mg -0.05 day't. m2 t= 59.91 days m WL en 2 = okt [:ent-lnB = ln A ] an2 = ln? t = 13.863 days for 301 (Stalf life) 0.96o. 2 t tog foc=0.96o. Eg becomes en lo = ento-ktog. toig = 0.105 K = 0.105 0.05 days" to.9 = 2.1 days