Answer:
Most spiral galaxies consist of a flat, rotating disk containing stars, gas and dust, and a central concentration of stars known as the bulge. ... The spiral arms are sites of ongoing star formation and are brighter than the surrounding disc because of the young, hot OB stars that inhabit them.
Explanation:
The correct is this because they said
Answer:
Hence the correct option is an option (b) Sr4, Cl,Br−,Na+.
Explanation:
Bromine and chlorine belong to an equivalent group. As we go down the group the dimensions increases which too there's a charge on the bromine atom. therefore the size of the Br- is going to be larger in comparison to the chlorine atom.
Sr atom is within the second group, and also it's below the above-mentioned atoms.so Sr is going to be the larger one among all the atoms.
Sodium and chlorine belong to an equivalent period .size decrease from left to right. but due to the charge on sodium its size decreases and there's an opportunity that Na+ size could be adequate for Cl.
Here we finally assume that two atoms are of an equivalent size (Na+ and Cl) which are less in size compared to the opposite two(Sr and Br-) during which one is greater (Sr)and the opposite is smaller(Br-).
Answer:
Equation of reaction:
a) 2HCl + Ba(OH)2 ==> CaCl2 + 2H2O
b) Molarity of base = 0.042 M.
Explanation:
Using titration equation
CAVA/CBVB = NA/NB
Where NA is the number of mole of acid = 2
NB is the number of mole of base = 1
CA is the molarity of acid =0.15M
CB is the molarity of base = to be calculated
VA is the volume of acid = 25 ml
VB is the volume of base = 44.45mL
Substituting
0.15×25/CB×44.45 = 2/1
Therefore CB =0.15×25×1/44.45×2
CB = 0.042 M.
