Find the concentration of sodium acetate when added to 0.1 M solution of acetic acid to form a buffer solution of $\mathrm{pH}=5.5$ ?

( $\mathrm{pK}_{\mathrm{a}}$ of $\mathrm{CH}_3 \mathrm{COOH}=4.5$ )

Which actinoid from following in its +3 state has largest size?

Which of the following halogens does always show oxidation state -1 ?

Which from following carbohydrates produces glucose, galactose and fructose on hydrolysis?