Question

can anyone tell me answer for 8 th one with explanation

Answer 1

Molar mass (molecular weight) of H3OCl is 54.4765 g/mol
mol of HCL = 1.5 * 2 = 3 mol
3 * 36.5 = 109.5gm mass of HClin the 2 dm3
109.5/2*1000 = 0.055 gm/ml
% w/v=0.055 * 100 =5.5 %w/v

H3OCL is hydrochloric acid solution
when HCl added to water it produce( H3O+ + Cl- ) ions in solution

Answer 2

Here, one mole of an sample always consist of 6.023×10^23 molecules.. That is avagrado number of atoms or molecules.
So,
Acc to the question no of mole= weight/molecular weight
n= 109.5/36.5=3
So for one mole 6.023*10^23 thempn for 3 moles of an sample contains
3*6.023*10^23 atoms or molecules