Directions (11-13) : Read the following passage carefully and answer the questions given below it.  

A poor Arab, travelling in the desert, was thirsty and tired, when he saw a spring. With a grateful heart he drank the water which he felt was extraordinarily sweet. He filled his leather bottle with the pure water, and continued on his way.   After many days he arrived at Baghdad. Securing an audience with the potentate, he gravely presented him with the leather bottle of water. It was the only gift he had.   The Caliph received the gift with great pleasure. Pouring some of the water into the goblet, he drank it, and then, thanking the poor Arab, rewarded him generously for his gift.   All the courtiers pressed forward, eager to taste the wonderful water. But the Caliphdenied them the privilege, even to his favourites.   When the Arab had departed with a happy heart, the Caliph explained why he had acted so strangely. The water in the leather bottle, because of its long storage, had become impure and foul tasting. He knew that if the others had tasted the water, they would have shown their disgust, and the poor man's feelings would have been wounded.  

Question-11 : The Arab gave the Caliph ______________ water to drink without knowing.