Solve this:
Q . The volume of water added to 500 mL, 0.5 M NaOH so that its strength becomes 10 mg NaOH per mL is
(1) 250 mL (2) 500 mL
(3) 750 mL (4) 1000 mL
Dear student ,
strength of NaOH = 10 mg / ml or 10 gm /L ; then molarity = strength / mol. mass. = 10 / 40 = 0.25 M
now ; let x ml water is to be added in 500 ml to prepare the desired conc.of NaOH
then from the molarity eq. before dilution after dilution
M1 V1 = M2 V2
O.5 500 = 0.25 (500 +x )
on solving ; 1000 = 500 + x
then x = 500 ml (option 2)
Regards
strength of NaOH = 10 mg / ml or 10 gm /L ; then molarity = strength / mol. mass. = 10 / 40 = 0.25 M
now ; let x ml water is to be added in 500 ml to prepare the desired conc.of NaOH
then from the molarity eq. before dilution after dilution
M1 V1 = M2 V2
O.5 500 = 0.25 (500 +x )
on solving ; 1000 = 500 + x
then x = 500 ml (option 2)
Regards