Question

Calculate the osmolarity of each of the following solutions. a. 0.39 M Na2CO3 b. 0.62 M Al(NO3)3 c. 4.2 M LiBr d. 0.009 M K3PO4

Answer 1

(a) Givn 0.39 M Na2CO3=0.39 mol/L

Na2CO3 ---------> 2Na⁺ + CO3^2-

1 mol of Na2CO3=2Osmol Na⁺ + 1Osmol CO3^2-=3 Osmol

Therefore the osmolarity=3 x 0.39 Osmol/L=1.17 Osmol/L.

(b) Given 0.62 M Al(NO3)3

Al(NO3)3 ------> Al⁺³ + 3NO3^-

1 mol of Al(NO3)3=4 Osmol

Therefore the osmolarity=4 x 0.0.62 Osmol/L=2.48 Osmol/L.

(c) Given 4.2 M LiBr

LiBr ----> Li⁺ + Br^-

1 mol of LiBr=2 Osmol

Therefore the osmolarity=2 x 4.2 Osmol/L=8.4 Osmol/L.

(d) Given 0.009 M K3PO4

K3PO4 ------> 3K⁺ + PO₄^3-

1 mol of K3PO4=4 Osmol

Therefore the osmolarity=4 x 0.009 Osmol/L=0.036 Osmol/L.

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