Questions

You have to consider three things.

1. First, are the bonds polar?

Look at differences in electronegativity and if  it is >0.5, bonds are polar.

2. Second, does the molecule have unshared electron pairs?

If so, they generally lead to a polar molecule.

3. Third, is the molecule symmetric?

If so, then although the bonds may be polar, the symmetry cancels out the individual bond polarity and the molecule is non polar.

CF4 follows all the rules above and has a symmetric distribution of charge, making it nonpolar. The others all have asymmetric charge distributions.

Hence, CF4 represents a Non-polar molecule.

FIFO (First In First Out) stack is used in 8086. In this type of Stack the First Stored Information is retrieved first.

a -  at the peak of changes in blood pressure indicates the systiolic pressure.

The World Environment Day (WED) is observed every year on June 5 to raise awareness about forests and wider issues of environmental protection. The 2017 theme is ‘Connecting People to Nature’. It implores us to get outdoors and into nature, to appreciate its beauty and to take forward the call to protect the Earth that we share. The host country for the WED 2017 is Canada, where the official celebrations take place.