Question

what will be the concentration of hydroxide ions if 185mg of Ca(OH)2 molar mass 74g/mole and 200g of NaOH molar mass 40g/mole are present in 500 ml of aqueous solution

Whoever ans. first and correctly I'll mark him as brainliest​

Answer 1

Answer:

The molarity is defined as the no.of moles per liter .For determining tge conc.of OH ions we need to calculate the no.of moles of OH ions produced by both compounds in 500ml of solution…

Molarity = No.of moles /Vol. of sol in litre

M = (mass/Molar mass)1000/V(ml)

For Ca(OH)2

Since we have given mass in miligrams but molar mass in grams so we need to convert mg into grams

1g =1000mg or 1mg =10^-3g then 185mg of Ca(OH)2 =0.185g

then M1 = (0.185/74)(1000/500) =0.005 molar

Ca(OH)2 ———→ Ca +2OH

thus 1 molar solution of Ca(OH)2 will produce 2 moles of OH ions and 0.005 molar will produce

2※0.005 moles = 0.01 moles of OH ions

Now for NaOH

200mg = 0.2g

them M2 = (0.2/40)(1000/500) =0.01 molar

NaOH-----> Na + OH

1 molar solution contains 1 mole of OH ions

and thus 0.01 molar will contain 0.01 moles of OH ions

Thus total no.of OH ions present will be sum of OH ions produced by both compounds

i.e 0.01+0.01 = 0.02 moles of OH ions….

Hope satisfied…