Match List-I with List-II:

	List-I Species		List-II Geometry/Shape
A.	H$$_3$$O$$^+$$	I.	Tetrahedral
B.	Acetylide anion	II.	Linear
C.	NH$$_4^+$$	III.	Pyramidal
D.	ClO$$_2^-$$	IV.	Bent

Choose the correct answer from the options given below:

We need to determine the geometry/shape of each species using VSEPR theory.

A. H$$_3$$O$$^+$$:

Central atom O has 3 bond pairs + 1 lone pair = 4 electron pairs (sp$$^3$$ hybridized).

Shape: Pyramidal (III)

B. Acetylide anion (C$$_2^{2-}$$):

The acetylide anion has a triple bond between two carbon atoms: $$[:C \equiv C:]^{2-}$$

Shape: Linear (II)

C. NH$$_4^+$$:

Central atom N has 4 bond pairs + 0 lone pairs = 4 electron pairs (sp$$^3$$ hybridized).

Shape: Tetrahedral (I)

D. ClO$$_2^-$$:

Central atom Cl has 2 bond pairs + 2 lone pairs = 4 electron pairs (sp$$^3$$ hybridized).

Shape: Bent (IV)

Therefore: A → III, B → II, C → I, D → IV