Answer:
In the option(A) moles of HCl left are 0.100 moles which is wrong, making the option incorrect.
Explanation:

Moles of HCl = n
Molarity of HCl = 1.0M
Volume of HCl solution = 30.0 mL = 0.030 L (1 mL = 0.001L)


Moles of Fe = 
According to recation , 1mol of Fe reacts with 2 mol HCl. Then 0.01 mole of Fe will recat with :
of HCl
This means that HCl uis in excess , hence excessive reagent.
Moles of HCl left unreacted :
= 0.030 mol - 0.020 mol = 0.010 mol
But in the option moles of HCl left are 0.100 moles which is wrong, making the option incorrect.
Answer:
Electromotive force or e.m.f is defined as the battery's energy per Coulomb of charge passing through it. like other measures of energy per charge emf has SI unit of volts , equivalent to joules per coulomb.
Answer:
The atmosphere traps heat energy from the Sun and energy radiated from Earth's surface helping to maintain Earth's climate
Explanation:
Earth's atmosphere keeps much of the Sun's energy from escaping into space. This process, called the greenhouse effect, keeps the planet warm enough for life to exist. The atmosphere allows about half of the Sun's heat energy (50%) to reach Earth's surface.
Answer: 0.405g
Explanation:
Molar Mass of Be = 9g/mol
Number of mole of Be = 0.045mol
Mass conc. Of Be = 0.045 x 9 = 0.405g
When atoms bond together to form molecules, they share or give electrons. If the electrons are shared equally by the atoms, then there is no resulting charge and the molecule is nonpolar.