Count Liquids Deflected by Charged Comb Stream Test

To determine the number of liquid streams deflected by a charged comb, we use the principle of electrostatic deflection of liquids containing polar molecules.

Principle:

When a charged object (such as a comb) is brought near a stream of a liquid, the electric field generated by the charge creates a non-uniform field.

• Liquids composed of polar molecules ($\mu \neq 0$, having a permanent dipole moment) experience an attractive electrostatic force regardless of whether the comb is positively or negatively charged, causing the stream to deflect toward the comb.
• Liquids composed of non-polar molecules ($\mu = 0$) do not possess a permanent dipole moment and do not show observable deflection.

---

Analysis of the Given Liquids:

1. $\text{O}_2$ (Liquid Oxygen):

   • A homonuclear diatomic molecule.
   • Dipole moment: $\mu = 0$ (Non-polar $\rightarrow$ No deflection).

2. $\text{HF}$ (Liquid Hydrogen Fluoride):

   • Heteronuclear diatomic molecule with high electronegativity difference between $\text{H}$ and $\text{F}$.
   • Dipole moment: $\mu \neq 0$ (Polar $\rightarrow$ Deflected).

3. $\text{H}_2\text{O}$ (Water):

   • Bent (V-shaped) geometry with lone pairs on oxygen, breaking symmetry.
   • Dipole moment: $\mu \neq 0$ (Polar $\rightarrow$ Deflected).

4. $\text{NH}_3$ (Liquid Ammonia):

   • Trigonal pyramidal geometry with a lone pair on nitrogen.
   • Dipole moment: $\mu \neq 0$ (Polar $\rightarrow$ Deflected).

5. $\text{H}_2\text{O}_2$ (Hydrogen Peroxide):

   • Non-planar open-book structure, leading to a net dipole moment.
   • Dipole moment: $\mu \neq 0$ (Polar $\rightarrow$ Deflected).

6. $\text{CCl}_4$ (Carbon Tetrachloride):

   • Highly symmetrical tetrahedral structure ($T_d$ symmetry) where individual $\text{C-Cl}$ bond dipoles cancel each other out completely.
   • Dipole moment: $\mu = 0$ (Non-polar $\rightarrow$ No deflection).

7. $\text{CHCl}_3$ (Chloroform):

   • Asymmetrical tetrahedral structure where bond dipoles do not cancel out.
   • Dipole moment: $\mu \neq 0$ (Polar $\rightarrow$ Deflected).

8. $\text{C}_6\text{H}_6$ (Benzene):

   • Symmetrical planar hexagonal ring ($D_{6h}$ symmetry).
   • Dipole moment: $\mu = 0$ (Non-polar $\rightarrow$ No deflection).

9. $\text{C}_6\text{H}_5\text{Cl}$ (Chlorobenzene):

   • Asymmetric polar molecule due to the electronegative chlorine atom attached to the benzene ring.
   • Dipole moment: $\mu \neq 0$ (Polar $\rightarrow$ Deflected).

---

Conclusion:

The liquids that exhibit deflection are those with $\mu \neq 0$: $\text{HF}, \text{H}_2\text{O}, \text{NH}_3, \text{H}_2\text{O}_2, \text{CHCl}_3, \text{and } \text{C}_6\text{H}_5\text{Cl}$

Total number of liquids showing deflection $= 6$.