Answer: A) copper(II) hydroxide Explanation: Sodium chloride: The solubility rules tell you that all halides are soluble with the exception of those formed with siver, mercury, and lead ions. Since this is not the case here, sodium chloride will be soluble.   Silver nitrate: It is soluble because all nitrates are soluble, without exception.   Potassium sulfate: It is soluble because all sulfates are soluble with the exception of those formed with silver, calcium, barium, mercury, lead, and strontium ions.   Copper (II) hydroxyde: It is insoluble because all hydroxides are insoluble with the exception of those formed with alkali metal ions and barium.

Answer: A) 88572 Explanation: Given a secret is told to 3 persons in 3 minutes.And if the process continues with each person saying 3 other persons,In 30 minutes => the rocess for 10 times because each person time is 3 minutes.Required number of persons = 3 + 32 + 33 + .... + 39 + 310   Now it forms a geometric progression,   Sum to n terms is S = arn - 1r - 1   Here a = 3, r = 3  => 59048 x 3 /2   = 88572.

Answer: D) Karnataka Explanation: Kunchikal falls of India is of height 1493 ft is in Karnataka state of the river Varahi.

A Bank Reconciliation Statement is a statement prepared periodically by a customer to explain the divergence (difference) between the bank balance as per cash book and the bank balance as per Pass Book. It clearly shows the two differing balances and the outstanding items which causes the balances to disagree. The objective of preparing such a statement is to know the causes of differences between the two balances and pass necessary correcting or adjusting entries in the books of the firm. But it is to be noted that some differences are automatically adjusted. For example - A cheque that has been sent for collection, but not yet collected, causes a difference between the balance as shown by the pass book and the balance as shown by the cash book, but no adjusting entry is required in the cash book for such a difference because, the bank will credit the firm’s account as soon as the cheque is collected.

Answer: C) Romans Explanation: Romans (753 BC - AD 410) began public health and sanitation systems.   Romans established the first public health and sanitation systems by building sewers and aqueducts. They also treated diseases with diet, exercise and meditation.

Answer: B) 5 m/h Explanation: As the distance travelled is constant, the time taken is inversely proportional to speed. Let 'u' be the speed of the current and 'v' be the speed of the boat. Speed of the boat downstream = v + u & upstream = v - u => v+u/v-u = 30/20 => v/u = 5 => v = 5u => v + u = 6u = 10/20/60 miles/hr => 6u = 30 m/h => u = 5 m/h

Answer: D) China and England Explanation: The Opium Wars were two wars in the mid-19th century involving Anglo-Chinese disputes over British trade in China and China’s sovereignty. The disputes included the First Opium War (1839–1842) and the Second Opium War (1856–1860).

Answer: C) lose electrons Explanation: Ionic bonding is the complete transfer of valence electron(s) between atoms. It is a type of chemical bond that generates two oppositely charged ions. In ionic bonds, the metal loses electrons to become a positively charged cation, whereas the nonmetal accepts those electrons to become a negatively charged anion.   Hence, when Ionic bonds are formed metallic atoms tend to lose electrons and become positive ions