instruction:
This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
question:
Passage: An alloy is a mixture of metals or a mixture of a metal and another element. Alloys are defined by metallic bonding character. An alloy may be a solid solution of metal elements (a single phase) or a mixture of metallic phases (two or more solutions). Intermetallic compounds are alloys with a defined stoichiometry and crystal structure. Zintl phases are also sometimes considered alloys depending on bond types (see also: Van Arkel-Ketelaar triangle for information on classifying bonding in binary compounds).
answer:
What is always a mixture of metal and other elements?


question:
Passage: The Finnish and Baltic invasions began a deterioration of relations between the Soviets and Germany. Stalin's invasions were a severe irritant to Berlin, as the intent to accomplish these was not communicated to the Germans beforehand, and prompted concern that Stalin was seeking to form an anti-German bloc. Molotov's reassurances to the Germans, and the Germans' mistrust, intensified. On June 16, as the Soviets invaded Lithuania, but before they had invaded Latvia and Estonia, Ribbentrop instructed his staff "to submit a report as soon as possible as to whether in the Baltic States a tendency to seek support from the Reich can be observed or whether an attempt was made to form a bloc."
answer:
Who wanted to know the moment an pro-german bloc was to form?


question:
Passage: Like other South Slavic languages, Serbo-Croatian has a simple phonology, with the common five-vowel system and twenty-five consonants. Its grammar evolved from Common Slavic, with complex inflection, preserving seven grammatical cases in nouns, pronouns, and adjectives. Verbs exhibit imperfective or perfective aspect, with a moderately complex tense system. Serbo-Croatian is a pro-drop language with flexible word order, subject–verb–object being the default. It can be written in Serbian Cyrillic or Gaj's Latin alphabet, whose thirty letters mutually map one-to-one, and the orthography is highly phonemic in all standards.
answer:

What kind of phonology does Serbian Cyrillic have?