TN State Board 12th Chemistry Question Paper 2024

Assertion is true because monoclinic sulphur crystallizes in the monoclinic crystal system. Reason is true because the defining parameters for the monoclinic system are $a \neq b \neq c$ and $\alpha = \gamma = 90^\circ, \beta \neq 90^\circ$. Since the assertion defines the system that the reason describes, the reason is the correct explanation.

The complex is an anionic coordination sphere $[Al(C_2O_4)_3]^{3-}$. The ligand is oxalate ($C_2O_4^{2-}$), named as oxalato. There are three of them, so 'trioxalato'. The metal Aluminium in an anionic complex is named as 'aluminate'. The oxidation state of Al: $x + 3(-2) = -3 \implies x = +3$. Hence, Potassium trioxalato aluminate (III).

Acid strength increases down the halogen group as the bond dissociation energy decreases. HI has the longest bond length and lowest bond dissociation energy among the hydrohalic acids, making the iodide ion a stable conjugate base and HI the strongest acid.

Dry ice is solid $CO_2$. In the $CO_2$ molecule, the carbon atom is $sp$ hybridized because it forms two double bonds (linear geometry). Fullerene, Graphite, and Graphene are all allotropes of carbon where carbon atoms are $sp^2$ hybridized.

RNA contains the nitrogenous bases Adenine, Guanine, Cytosine, and Uracil. Among these, the pyrimidines are Cytosine and Uracil. Thiamine (Thymine) is found in DNA, not RNA.