Ncert Solutions Chemistry Class 12th

Molar mass of Nalorphene = 311g/mol

Now 1000g of solution contains 1.5 * 10^-3 moles of Nalorphene (Molality of solution = moles of solute/mass of solvent (in kg)

⇒ 1.5 * 10^-3 moles of Nalorphene = 1.5 * 10^-3 * 311 = 0.4665g of Nalorphene

Therefore, total mass of the solution = (1000 + 0.4665) g

⇒ total mass = 1000.4665 g

This implies that the mass of the solution containing 0.4665 g of nalorphene is 1000.4665 g.

Therefore, mass of the solution containing 1.5 mg of nalorphene is:

Mass = 1000.4665 X 1.5 X 10^-3 / 4.665 g

⇒ mass of solution containing required ions = 3.22 g

Hence, the mass of aqueous solution required is 3.22 g.

16.16 

Magnesium or Aluminium hydroxides do not tackle with the root cause of acidity that is they reduce the acidity by reacting with excess acid present in the stomach [neutralization reaction].

On the other hand cimetidine and ranitidine relieve acidity by preventing interaction of histamine with receptors of stomach walls and hence release of excess acid by stomach walls is stopped. So the root cause of acidity is totally eliminated.

Therefore cimetidine and ranitidine relieve the acidity by tackling the root cause whereas magnesium or aluminum hydroxide just relieves by healing only the mere cause of acidity.

Total mass of solution = 6.5g + 450g = 456.5g

Therefore mass percentage of aspirin in solution = (mass of aspirine/total mass of solution) = 6.5/456.5

⇒ mass % of aspirine = 1.424%

16.15 

Antiseptics and disinfectants are effective against micro-organisms. Antiseptics are applied to the living tissues such as wounds, cuts, ulcers, and diseased skin surfaces, while disinfectants are applied only to inanimate objects such as floors, drainage system, instruments, etc. Disinfectants are harmful to the living tissues. Iodine is an example of a strong antiseptic. Tincture of iodine (2 − 3 percent of solution of iodine in alcohol − water mixture) is applied to wounds. 1 percent solution of phenol is used as a disinfectant.

The Solubility product of CuS (ksp) = 6 * 10^-16

CuS → Cu ⁺⁺ + S^2-

Let the s be solubility of CuS in mol/L

Ksp = [ Cu ⁺⁺ ] [S²]

Ksp = solubility product

6 * 10^-16 = s * s = s²

⇒ S = 2.45 * 10^-8 mol/L

Hence, the maximum molarity of CuS in an aqueous solution is 2.45 * 10^-8 mol/L

16.14 

Antibiotics that are effective against a wide range of gram-positive and gram-negative bacteria are known as broad spectrum antibiotics. Chloramphenicol is an example of a broad spectrum antibiotic. It has the following structure: -

It can be used for the treatment of typhoid, dysentery, acute fever, pneumonia, meningitis, and certain forms of urinary infections. Two other examples of broad spectrum antibiotics are vancomycin and ofloxacin. Ampicillin and amoxicillin? synthetically modified from penicillin are also broad spectrum antibiotics.

Mass of ions = 92g

Molar mass of ions = Na⁺ = 23g (neglect the mass lost due to absence of a electron)

Moles of ions = mass of ions/molar mass

⇒ n = 92/23 moles

⇒ n = 4moles

Molality of solution = moles of solute/mass of solvent (in kg) Molality = 4/1 = 4M

16.13 

Anti-depressant drugs are needed to counteract the effect of depression. These drugs function by inhibiting the enzymes catalysing the degradation of the neurotransmitter, noradrenaline. As a result, the important neurotransmitter is slowly metabolised and then it can activate its receptor for longer periods of time.

Two anti-depressant drugs are:

(i) Iproniazid

(ii) Phenelzine

16.12

Specific drugs affect only some specific or particular receptors. Antacids and anti-allergic drugs work on different receptors. This is the reason why antacids and anti-allergic drugs do not interfere with each other's functions, but interfere with the functions of histamines.