In silica (SiO2), each silicon atom is bonded to
two oxygen atoms
four oxygen atoms
one silicon and two oxygen atoms
one silicon and four oxygen atoms
In the equation
CrO + SO
the oxidation number of Cr changes from
+6 to +4
+6 to +3
+8 to +4
+4 to +3
In Kjeldahl's method of estimation of nitrogen, CuSO4 acts as
oxidising agent
reducing agent
catalytic agent
hydrolysis agent
C.
catalytic agent
Kjeldahl's method is used for the estimation of nitrogen. The organic compound is heated with conc. H2SO4 in presence of K2SO4 (used to elevate boiling point of H2SO4) and CuSO4 (used as catalyst) to convert all the nitrogen into (NH4)2SO4.