1. Write the formula of lead sulphate

2. Mention the general formula of alkyne compounds

3. Which allotrope of carbon is very hard

4. How does the atomic radius change as you go from left to right on a periodic table

5. Write the valency of an element having atomic number 13

6. The type of image formed by eye lens is

7. ENT specialist uses ---- in small aperture

8. The SI unit of the electric power is

9. A fuel gas that is produced anaerobically from biomass is

Here are the answers to your questions:

1. Formula of Lead Sulphate

The chemical formula for lead sulphate is PbSO₄.

2. General Formula of Alkyne Compounds

Alkynes are hydrocarbons with a triple bond between carbon atoms. Their general formula is C_nH_2n-2, where n is the number of carbon atoms.

3. Hard Allotrope of Carbon

The allotrope of carbon that is known for its hardness is diamond.

4. Atomic Radius Trend Across the Periodic Table

As you move from left to right across a period in the periodic table, the atomic radius generally decreases. This is due to the increasing positive charge in the nucleus, which pulls the electrons closer.

5. Valency of Element with Atomic Number 13

The element with atomic number 13 is aluminum (Al), and its valency is 3.

6. Type of Image Formed by Eye Lens

The eye lens forms a real and inverted image on the retina.

7. Instrument Used by ENT Specialist

An ENT specialist uses a otoscope in a small aperture to examine the ear.

8. SI Unit of Electric Power

The SI unit of electric power is the watt (W).

9. Anaerobically Produced Fuel Gas

A fuel gas produced anaerobically from biomass is known as biogas.