CA
Question : Which of the following metal salts is responsible for permanent hardness in water?
Option 1: KCl
Option 2: Nacl
Option 3: Ca(HCO3)2
Option 4: CaCl2
Correct Answer: Ca(HCO3)2
Solution : The correct option is Ca(HCO3)2.
The presence of bicarbonates of calcium and magnesium causes water to become temporarily hard, but the presence of soluble chlorides and sulphates of calcium and magnesium causes permanent hardness. Calcium bicarbonate, also called calcium hydrogen carbonate, has the chemical formula Ca(HCO3)2.
Question : If a + b + c = 19, ab + bc + ca = 120, then what is the value of a3 + b3 + c3 – 3abc?
Option 1: 18
Option 2: 23
Option 3: 31
Option 4: 19
Correct Answer: 19
Solution : Given, a + b + c = 19 and ab + bc + ca = 120 We know, a3 + b3 + c3 – 3abc = (a + b + c) [(a + b + c)2 – 3(ab + bc + ca)] = 19[192 – 3 × 120] = 19[361 – 360] = 19 × 1 = 19 Hence, the correct answer is 19.
Question : Directions: Which one set of letters when sequentially placed at the gaps in the given letter series shall complete it? _ab _ b _ bc _ ca _
Option 1: accbb
Option 2: abcca
Option 3: cacab
Option 4: abacb
Correct Answer: cacab
Solution : Given: _ab _ b _ bc _ ca _
To fill the series we have to divide the series – _ab / _ b _ / bc _ / ca _ Let's check each option – First option: accbb; aab / cbc / bcb / cab (No repeated pattern has been found.) Second option: abcca; aab / bbc / bcc / caa (No repeated pattern has been found.) Third option: cacab; cab / abc / bca / cab (In each part the letters are being shuffled – the first letter is moved to the third position in the next part and the second and third letters are moved to the first and second positions respectively.) Fourth option: abacb; aab / bba / bcc / cab (No repeated pattern has been found.)
So, the series becomes→cababcbcacab. Hence, the third option is correct.
Hey vidhisha same question????
Hello,
There's a lot of confusion going on due to the old syllabus and new syllabus but it's pretty easy and clear that you are not required to pay for your registration fee again as it is valid for 3 years but yes, you will have to pay your examination fee and prepare according to the new syllabus.
I hope this clears your doubts.
All the best
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