HF is not preserved in glass bottle because :
it reacts with the visible part of the light
it reacts with the sodium oxide of the glass
it reacts with the aluminium oxide of the glass composition
it reacts with SiO2 of the glass
In a lead storage battery , reaction at cathode is :
Pb + SO42- PbSO4 + 2e-
Pb + PbO2 + 2H2SO4 2PbSO4 + 2H2O
PbSO4 + 2e- Pb + SO42-
PbO2 + 4H+ + SO42- + 2e- PbSO4 + 2H2O
In coagulating the colloidal solution of As2S3 .which has the minimum coagulating value ?
NaCl
KCl
BaCl2
AlCl3
D.
AlCl3
Hardy-Schulze rule : The coagulating effect of an ion on dispersed phase of opposite charge increases with the valence of the ions . e.g ,
For precipitating (coagulating) of an As2S3 sol (negative sol) , the coagulating power of Al3+ , Ba2+ , Na+ ions are in the order ;
Al3+ > Ba2+ > Na+