MISCONCEPTIONS OF HIGH SCHOOL STUDENTS IN SALT HYDROLYSIS TOPIC USING A THREE-TIER DIAGNOSTIC TEST (TTDT)

This study aims to find out whether high school students in Surakarta have misconceptions in salt hydrolysis material and to find out which concept is the most misconception experienced by high school students in Surakarta in salt hydrolysis material. This study used a descriptive approach. Data collection techniques using data triangulation technique from the results of the Three-Tier Diagnostic Test (TTDT), formative tests, and interviews. The sample used in this study was determined using a purposive sampling technique. Based on the research conducted, high school students in Surakarta experienced misconceptions in salt hydrolysis material as much as 36.75%, 35.94% Scientific knowledge, 15.63% lack of knowledge, and 10.90% error. Most misconceptions experienced by high school students in Surakarta on salt hydrolysis material occur in sub concepts: a) conclude the acid-base properties shown from salt solutions (49.91%), b) calculate the pH of the salt solution (39.15), c) analyze the reaction salt hydrolysis (37.21%), d) analyze the concept of hydrolysis that occurs in solution (35.98), e) determine the types of hydrolysis of salt (21.87%).


INTRODUCTION
The 21st century marked by the rapid development of science and technology in the field of life in society, especially information and communication technology [1]. The needs of the 21st century as it is now essential knowledge skills (cognitive) in-depth in the context of life regarding a problem, event, or event [2]. The rapid development of science and technology makes many countries compete with each other.
The competition is to show the quality and consistency of a nation [3]. One of the things that can be prepared in the face of competition with people from other countries is to obtain sufficient education as a provision to compete in the community.
Education is a source of national progress that determines the competitiveness of a nation [3]. If people have a low level of education, it will be difficult for people to compete with people from other countries. At present, education in  DAN PENDIDIKAN KIMIA), Vol. 5, No. 1, 2020, pp. 32-42 33 learning, which when learning takes place, students are more active and not teachercentered.
One of the obligatory subject in sciences is chemistry. Chemistry is a subject based on abstract concepts, so it is difficult to understand, especially when students are in a position to believe in something without seeing (believe without seeing) [4]. One of the difficulties students face in learning chemistry because learning chemistry is complex and abstract. Chemistry consists of three levels of representation, namely (a) macroscopic (everything that can be seen, touched, and felt), (b) submicroscopic (atoms, molecules, ions, and structures), and (c) symbolic (symbols, formulas, mathematical equations, graphs, molecular structures, diagrams, and others.) [5]. In addition, science is very close to a concept, which is a vital and essential concept in learning chemistry. The concept is a fundamental thing that is very instrumental in understanding a lesson [6]. Therefore, students usually try to understand and build their concepts to make it easier to learn. However, when students understand or build a concept by selecting information from the teacher, books, or the environment to improve their cognitive structure, students can make mistakes that will cause a concept error or commonly called misconception.
A misconception is a different understanding from the understanding accepted by the scientific community [7]. In learning chemistry, the concepts are arranged hierarchy so that if the basic concept experiences a misconception, it will cause a misconception in the next concept [8]. A misconception has meaning as an inaccurate concept, the use of wrong concepts, wrong classification of examples, chaos of different concepts, and hierarchical relationships of concepts that are not true [9]. In addition, misconception as a contradiction or incompatibility of concepts understood by someone with the concepts used by the experts of science concerned [10]. Therefore, a misconception is a problem faced by 21st-century students. Students in the 21st century must have four competencies, namely, conceptual understanding, critical thinking, creative thinking, and collaboration, and communication [11]. Conceptual understanding is one important indicator to achieve the success of learning science [1]. Understanding the concept has a relationship with misconception, understanding the concept of mastery of concepts by the agreement of scientists, does not deviate, and does not cause other hypotheses that can cause cognitive conflict. In contrast, a misconception is a misconception with scientific understanding, which is accepted by experts.
Previous studies have shown that in salt hydrolysis material, students who have applied three chemical representations (macroscopicsubmicroscopic-symbolic).There are only 3% that comprehended those three, students who are at the macroscopic-symbolic level of 97%, and at 0% submicroscopic-symbolic levels [12].
These results indicate that students' scientific reasoning on hydrolysis material is still low. This research resulted in students' scientific reasoning ability at the level of no response by 1%, non-normative 33%, general descriptive 40%, Bronsted causal 26%, and Bronsted mechanistic 0%. At the non-normative level, it means that there is an explanation, but it is not conceptual. This finding can be made possible due to misconceptions experienced by students.
Besides, previous studies have found that 46% of students experience misconceptions about salt hydrolysis material [13]. Salt hydrolysis material was also detected using an interview sheet instrument, and it was found that 37.22% of students experienced misconceptions on this material [14].
Misconceptions can be identified using several methods, namely concept maps, written essay tests, interviews, class discussions, and diagnostic tests. A diagnostic test is a test used to find weaknesses (misconceptions) on a particular topic and get input on student responses to correct their weaknesses [8]. This test has several types, namely two-tier multiple-choice and three tiers multiple choice. Two-tier Multiple-Choice is a multiplechoice test consisting of two layers or levels.
In the first layer are questions and answer choices. Whereas in the second layer, in the form of reasons for the answers chosen in the first layer [15]. This test has a weakness that is not able to distinguish students who experience misconceptions, errors, do not understand the concept, and understand the concept, so it can not be ascertained whether students' mistakes are caused by misconceptions, errors, or lack of knowledge [17].
Three-tier diagnostic test (TTDT) has three JKPK (JURNAL KIMIA DAN PENDIDIKAN KIMIA), Vol. 5, No. 1, 2020, pp. 32-42 35 layers. The first layer is a question, the second layer is a reason, and the third layer is a student's confidence in choosing an answer [15]. TTDT has the advantage of being able to distinguish between students who do not understand concepts, who experience misconceptions, and who already understand concepts. In the three-tier test can identify the existence of misconceptions that are supported by strong beliefs and not only because they answer incorrectly on the questions and reasons. Also, the Three-tier diagnostic test (TTDT) is proper for detecting the location of misconceptions [18].
The identification of the misconception was carried out in three high schools in Surakarta, where students from the three high schools had high cognitive abilities so that it was possible for many students to experience misconceptions. Research on misconceptions has been conducted on students who have high cognitive levels, and low cognitive levels, resulting in students who have high cognitive levels have more misconceptions than students who have low cognitive levels [19].

RESULTS AND DISCUSSION
The identification of students' mis-  broken down into cations and anions by water. Previous research also found the same misconception, which states that the water is causing the separation of salt into cations and anions [22]. This analysis is not following the statement that hydrolysis is the reaction between water and salt cations or anions to produce H3O + and OHions due to the transfer of protons between ions and water [22]. Hydrolysis comes from the word hydro, which means water, and lysis means decomposition [23]. So salt hydrolysis is a breakdown of water by ions from salt.  DAN PENDIDIKAN KIMIA), Vol. 5, No. 1, 2020, pp. 32-42 [14]. The more difficult it is to remove protons from the acid, and the easier it is for anions or their conjugate bases to attach protons from water (meaning hydrolysis) [26].
Misconceptions in subconcepts con- because it can blue paper litmus red. This misconception is following previous research, which states that the rate of change of litmus paper can be used as information to determine the strength of acid [27]. This result is not suitable for the concept that litmus paper is an indicator to determine the acid/base properties of a solution. So litmus paper is not the reason the solution can be acidic/basic. The acidic nature of a salt solution is because the ions from the salt can cause hydrolysis, which will produce H + or OHions so that the solution can be acidic or basic [14].
Based on the discussion above, in this study, it was found that a misconception experienced by students is salt decomposed

ACKNOWLEDGMENT
The author thanks the principals of state high school in Surakarta for the permission given to the author to carry out research.