19,000+ solved questions for JEE Advanced, JEE Mains, NEET & IChO — with answers and expert explanations.
Darkening of surface painted with white lead is due to (CPMT 2009)
Which amont the following is not a borane? (AMU 2009)
The lead of the lead pencils melts at (AIIMS 2009) p-BLOCK (Group 13 - 14)
The stability of +1 oxidation state increases in the sequence (AIPMT 2009)
The tendency of group 14 elements to show +2 oxidation state increases in the order of
Which of the following ions is the most stable ?
A type of zeolite used to convert alcohols directly into gasoline is
Which of the following is the correct statement about silicones ?
Which one of the following anions is present in the chain structure silicates ? (a) Si O - (b) n (Si O ) - (c) n (SiO ) - (d) SiO - Ans. (c) Sol. There are two general formula of anions of chain silicates are n SiO - …
In SiO , - the tetrahedral molecule, two oxygen atoms are shared in
Glass and cement are two important examples of
Silicon is an important constituent of
Which of the following acids cannot be stored in glass ?
CO2 is not a poisonous gas but there is increase in concentration of CO2 in the atmosphere due to burning of fossil fuels and decompostion of limestone. The increase in concentration of CO2 may lead to
Which of the following is not true about structure of carbon dioxide ?
Which is not a method of preparing carbon monoxide on a commercial scale ? (a) 473 1273 K (s) (g) (g) 2(g) C H O CO H - + ¾¾¾¾¾® + (b) 1273 K (s) 2(g) 2(g) (g) 2(g) 2C O 4N 2CO 4N + + ¾¾¾® + (c) (g) (s) 2(g) 2C O 2CO …
Assertion : SiF - is known but SiCl - is not. Reason : Size of fluorine is small and its lone pair of electrons interacts with d-orbitals of Si strongly.
Compound (B) is:
Compound (A) is:
Aluminium becomes passive in:
Which one of the following metals cannot be extracted by using Al as a reducing agent?
Anodised aluminium is :
Thermite a mixture used for welding is:
The reaction which is not involved in thermite process: (a) 3Mn O 8Al 9Mn 4Al O + ¾¾® + (b) Cr O 2Al 2Cr Al O + ¾¾® + (c) 2Fe Al O Fe O 2Al + ¾¾® + (d) B O 2Al 2B Al O + ¾¾® +
Anodising can be done by electrolysing dilute H2SO4 with aluminium as anode. This results in :