Select the graph that correctly describes the adsorption isotherms at two temperatures T₁, and T₂ (T₁ > T₂) for a gas :

(x - mass of the gas absorbed ; m - mass of adsorbent ; P - pressure)

The major component/ingredient of Portland Cement is :

In the structure of the dichromate ion, there is a :

Which one of the following compounds contains $$\beta$$-C₁-C₄ glycosidic linkage?